Use of ``Cold Spell'' indices to quantify excess chronic obstructive pulmonary disease (COPD) morbidity during winter (November to March 2000-2007): case study in Porto

NASA Astrophysics Data System (ADS)

Monteiro, Ana; Carvalho, Vânia; Góis, Joaquim; Sousa, Carlos

2013-11-01

The aim of this study was to examine the relationship between the occurrence of cold episodes and excess hospital admissions for chronic obstructive pulmonary disease (COPD) in Porto, Portugal, in order to further understand the effects of cold weather on health in milder climates. Excess COPD winter morbidity was calculated from admissions for November to March (2000-2007) in the Greater Porto Metropolitan Area (GPMA). Cold spells were identified using several indices (Díaz, World Meteorological Organization, Cold Spell Duration Index, Australian Index and Ondas’ Project Index) for the same period. Excess admissions in the periods before and after the occurrence of cold spells were calculated and related to the cold spells identified. The COPD seasonal variation admission coefficient (CVSA) showed excess winter admissions of 59 %, relative to other months. The effect of cold spell on the aggravation of COPD occurs with a lag of at least 2 weeks and differs according to the index used. This study indicates the important role of the persistence of cold periods of at least 2 weeks duration in the increase in COPD admissions. The persistence of moderate temperatures (Tmin ≤5 °C) for a week can be more significant for increasing COPD admissions than very low temperatures (Tmin ≤ 1.6 °C) for just a few days. The Ondas projects’ index provides the most accurate detection of the negative impacts of cold persistency on health, while the Diaz index is better at evaluating the consequences of short extreme cold events.

Are the current thresholds, indicators, and time window for cold warning effective enough to protect cardiovascular health?

PubMed

Lin, Shao; Lawrence, Wayne R; Lin, Ziqiang; DiRienzo, Stephen; Lipton, Kevin; Dong, Guang-Hui; Leung, Ricky; Lauper, Ursula; Nasca, Philip; Stuart, Neil

2018-10-15

More extreme cold weather and larger weather variations have raised concerns regarding their effects on public health. Although prior studies assessed the effects of cold air temperature on health, especially mortality, limited studies evaluated wind chill temperatures on morbidity, and health effects under the current cold warning threshold. This study identified the thresholds, lag periods, and best indicators of extreme cold on cardiovascular disease (CVD) by comparing effects of wind chill temperatures and cold air temperatures on CVD emergency department (ED) visits in winter and winter transition months. Information was collected on 662,625 CVD ED visits from statewide hospital discharge dataset in New York State. Meteorological factors, including air temperature, wind speed, and barometric pressure were collected from National Oceanic and Atmospheric Administration. A case-crossover approach was used to assess the extreme cold-CVD relationship in winter (December-February) and transition months (November and March) after controlling for PM 2.5 . Conditional logistic regression models were employed to analyze the association between cold weather factors and CVD ED visits. We observed CVD effects occurred when wind chill temperatures were as high as -3.8 °C (25 °F), warmer than current wind chill warning standard (≤-28.8 °C or ≤-20 °F). Wind chill temperature was a more sensitive indicator of CVD ED visits during winter with temperatures ≤ -3.8 °C (25 °F) with delay effect (lag 6); however, air temperature was better during transition months for temperatures ≤ 7.2 °C (45 °F) at earlier lag days (1-3). Among all CVD subtypes, hypertension ED visit had the strongest negative association with both wind chill temperature and air temperature. This study recommends modifying the current cold warning temperature threshold given larger proportions of CVD cases are occurring at considerably higher temperatures than the current criteria. We also recommend issuing cold warnings in winter transitional months. Copyright © 2018 Elsevier B.V. All rights reserved.

Relative roles of temperature and photoperiod as drivers of metabolic flexibility in dark-eyed juncos.

PubMed

Swanson, David; Zhang, Yufeng; Liu, Jin-Song; Merkord, Christopher L; King, Marisa O

2014-03-15

Seasonal phenotypic flexibility in small birds produces a winter phenotype with elevated maximum cold-induced metabolic rates (=summit metabolism, Msum). Temperature and photoperiod are candidates for drivers of seasonal phenotypes, but their relative impacts on metabolic variation are unknown. We examined photoperiod and temperature effects on Msum, muscle masses and activities of key catabolic enzymes in winter dark-eyed juncos (Junco hyemalis). We randomly assigned birds to four treatment groups varying in temperature (cold=3°C; warm=24°C) and photoperiod [short day (SD)=8 h:16 h light:dark; long day (LD)=16 h:8 h light:dark] in a two-by-two design. We measured body mass (Mb), flight muscle width and Msum before and after 3 and 6 weeks of acclimation, and flight muscle and heart masses after 6 weeks. Msum increased for cold-exposed, but not for warm-exposed, birds. LD birds gained more Mb than SD birds, irrespective of temperature. Flight muscle size and mass did not differ significantly among groups, but heart mass was larger in cold-exposed birds. Citrate synthase, carnitine palmitoyl transferase and β-hydroxyacyl Co-A dehydrogenase activities in the pectoralis were generally higher for LD and cold groups. The cold-induced changes in Msum and heart mass parallel winter changes for small birds, but the larger Mb and higher catabolic enzyme activities in LD birds suggest photoperiod-induced changes associated with migratory disposition. Temperature appears to be a primary driver of flexibility in Msum in juncos, but photoperiod-induced changes in Mb and catabolic enzyme activities, likely associated with migratory disposition, interact with temperature to contribute to seasonal phenotypes.

Winter CO2 efflux from cold semiarid sagebrush shrublands distributed across the rain-to-snow transition zone

NASA Astrophysics Data System (ADS)

Fellows, A.; Flerchinger, G. N.; Lohse, K. A.; Seyfried, M. S.

2017-12-01

Predicting winter CO2 efflux across the rain-to-snow transition zone is challenging in the cold semiarid northern Great Basin, USA, complicated by steep environmental gradients and marked heterogeneity in ecosystem properties. We therefore examined winter CO2 efflux over 9 site-years using 4 eddy covariance towers located in the Reynolds Creek Critical Zone Observatory. The sites were sagebrush shrublands located at 1425, 1680, 2098, and 2111 m, and spanned a large part of the rain-to-snow transition zone. We focused on two objectives. First, we quantified winter CO2 efflux at the sites, and considered how these varied with elevation. Second, we used a within-site and cross-site analysis to examine the biological and physical factors that impact winter CO2 efflux. Winter conditions were identified using temperature, snow depth, and CO2 exchange measurements and included 12,922 observations. The duration of winter conditions increased from 90 to 180 days with elevation. Peak snow depth increased from < 30 to > 100 cm with elevation. Cumulative winter CO2 efflux accounted for > 10% of the total annual CO2 efflux, increased with elevation, and was a key component of net ecosystem production at some sites in some years. The importance of winter CO2 efflux was accentuated by the region's long winters and also dry summers that decreased water availability and decomposition during non-winter periods. Preliminary regressions examining air temperature, soil temperature, wind speed, snow depth, and gross carbon uptake indicated some of these factors control the rate of winter CO2 efflux and require consideration, but that additional work is needed to disentangle co-linearity and assess the importance of these factors within and between sites. These findings suggest a consideration of winter CO2 efflux is warranted in cold winter-wet semiarid ecosystems, particularly where winters are long and non-winter CO2 efflux is strongly limited by water availability.

Factors contributing to deep supercooling capability and cold survival in dwarf bamboo (Sasa senanensis) leaf blades.

PubMed

Ishikawa, Masaya; Oda, Asuka; Fukami, Reiko; Kuriyama, Akira

2014-01-01

Wintering Sasa senanensis, dwarf bamboo, is known to employ deep supercooling as the mechanism of cold hardiness in most of its tissues from leaves to rhizomes. The breakdown of supercooling in leaf blades has been shown to proceed in a random and scattered manner with a small piece of tissue surrounded by longitudinal and transverse veins serving as the unit of freezing. The unique cold hardiness mechanism of this plant was further characterized using current year leaf blades. Cold hardiness levels (LT20: the lethal temperature at which 20% of the leaf blades are injured) seasonally increased from August (-11°C) to December (-20°C). This coincided with the increases in supercooling capability of the leaf blades as expressed by the initiation temperature of low temperature exotherms (LTE) detected in differential thermal analyses (DTA). When leaf blades were stored at -5°C for 1-14 days, there was no nucleation of the supercooled tissue units either in summer or winter. However, only summer leaf blades suffered significant injury after prolonged supercooling of the tissue units. This may be a novel type of low temperature-induced injury in supercooled state at subfreezing temperatures. When winter leaf blades were maintained at the threshold temperature (-20°C), a longer storage period (1-7 days) increased lethal freezing of the supercooled tissue units. Within a wintering shoot, the second or third leaf blade from the top was most cold hardy and leaf blades at lower positions tended to suffer more injury due to lethal freezing of the supercooled units. LTE were shifted to higher temperatures (2-5°C) after a lethal freeze-thaw cycle. The results demonstrate that the tissue unit compartmentalized with longitudinal and transverse veins serves as the unit of supercooling and temperature- and time-dependent freezing of the units is lethal both in laboratory freeze tests and in the field. To establish such supercooling in the unit, structural ice barriers such as development of sclerenchyma and biochemical mechanisms to increase the stability of supercooling are considered important. These mechanisms are discussed in regard to ecological and physiological significance in winter survival.

Change of Martian surface height associated with polar cold spots

NASA Astrophysics Data System (ADS)

Ford, P. G.; Pettengill, G. H.

2003-12-01

For the past 30 years, orbiting microwave radiometers have observed anomalously low emission temperatures during Martian polar winters. While the physical surface temperature cannot drop significantly below 148K---the point at which CO2 starts to condense---radiometric temperatures of 110K or lower at 25μ wavelength are commonly found in isolated ``cold spots'' throughout both northern and southern polar winters. These form roughly circular patches, tens to hundreds of km in diameter, and persist for no more than a few days. Three models have been proposed to account for them: (a) an atmospheric effect that accompanies CO2 snowfall; (b) fresh surface deposits of CO2 snow; or (c) a change in the properties of CO2 slab ice. Following the success of Smith et al.1 in using the MOLA laser altimeter aboard Mars Global Surveyor to directly measure the growth of the winter polar caps, we have applied the same technique to ask whether cold spots are accompanied by a sudden change in surface height. To identify the cold spots, we first examined all polar observations made by the TES radiometer that was co-boresited with MOLA, and made gridded images of ∂ T / ∂ λ , the derivative of the brightness temperature wrt wavelength, 20μ <= λ <= 25μ , over 5o ranges in Ls. A total of 169 cold spots were readily located in the 3 winters (one northern, two southern) during which MOLA operated, and their times of first appearance were noted. We then examined the individual MOLA tracks that crossed these regions from 30 days before, to 30 days after, the cold spot appearances. Three sets of crossing points were assembled: (a) both pairs of tracks were made before the cold spot appearance, (b) both after the appearance, and (c) one before and the other after. For each crossing point, the surface height was interpolated from the 3 nearest altimeter footprints in each of the two tracks. The difference between the resulting pair of heights was averaged over all crossing points, and the RMS variance of the height differences was used as a measure of the statistical error in the measurement. Preliminary results show small height differences before the appearance of a cold spot, as expected, but no abrupt jump in surface height immediately after one appears. This suggests that the cold spots are not formed by deep (>50cm) CO2 snow deposits, but it cannot help us decide between the alternatives of CO2 snowfall or a change in slab ice properties. 1 Smith, Zuber, and Neumann, Science, {294}, 2141-2146, 2001.

Disruption of the European climate seasonal clock in a warming world

NASA Astrophysics Data System (ADS)

Cattiaux, J.; Cassou, C.

2015-12-01

Strength and inland penetration of the oceanic westerly flow over Europe control a large part of the temperature variability over most of the continent. Reduced westerlies, linked to high-pressure anomalies over Scandinavia, induce cold conditions in winter and warm conditions in summer. Here we propose to define the onset of these two seasons as the calendar day where the daily circulation/temperature relationship over Western Europe switches sign. According to this meteorologically-based metrics assessed from several observational datasets, we provide robust evidence for an earlier summer onset by ~10 days between the 1960s and 2000s. Results from model ensemble simulations dedicated to detection-attribution show that this calendar advance is incompatible with the sole internal climate variability and can be attributed to anthropogenic forcings. Late winter snow disappearance over Eastern Europe affects cold air intrusion to the West when easterlies blow, and is mainly responsible for the observed present-day and near-future summer advance. Our findings agree with phenological-based trends (earlier spring events) reported for many living species over Europe, for which they provide a novel dynamical interpretation beyond the traditionally evoked global warming effect. Based on business-as-usual scenario, a seasonal shift of ~25 days is expected by 2100 for summer onset, while no clear signal arises for winter onset.

A synoptic approach to weather conditions discloses a relationship with ambulatory blood pressure in hypertensives.

PubMed

Morabito, Marco; Crisci, Alfonso; Orlandini, Simone; Maracchi, Giampiero; Gensini, Gian F; Modesti, Pietro A

2008-07-01

Higher blood pressure (BP) values in cold than in hot months has been documented in hypertensives. These changes may potentially contribute to the observed excess winter cardiovascular mortality. However, the association with weather has always been investigated by considering the relationship with a single variable rather than considering the combination of ground weather variables characterizing a specific weather pattern (air mass (AM)). We retrospectively investigate in Florence (Italy) the relationship between BP and specific AMs in hypertensive subjects (n = 540) referred to our Hypertension Unit for 24-h ambulatory BP monitoring during the period of the year characterized by the highest weather variability (winter). Five different winter daily AMs were classified according to the combination of ground weather data (air temperature, cloud cover, relative humidity, atmospheric pressure, wind speed, and direction). Multiple variable analysis selected the AM as a significant predictor of mean 24-h BP (P < 0.01 for diastolic BP (DBP) and P < 0.05 for systolic BP (SBP)), daytime DBP (P < 0.001) and nighttime BP (P < 0.01 for both SBP and DBP), with higher BP values observed in cyclonic (unstable, cloudy, and mild weather) than in anticyclonic (settled, cloudless, and cold weather) days. When the association with 2-day sequences of AMs was considered, an increase in ambulatory BP followed a sudden day-to-day change of weather pattern going from anticyclonic to cyclonic days. The weather considered as a combination of different weather variables may affect BP. The forecast of a sudden change of AM could provide important information helpful for hypertensives during winter.

Deacclimation may be crucial for winter survival of cereals under warming climate.

PubMed

Rapacz, Marcin; Jurczyk, Barbara; Sasal, Monika

2017-03-01

Climate warming can change the winter weather patterns. Warmer temperatures during winter result in a lower risk of extreme freezing events. On the other hand the predicted warm gaps during winter will decrease their freezing tolerance. Both contradict effects will affect winter survival but their resultant effect is unclear. In this paper, we demonstrate that climate warming may result in a decrease in winter survival of plants. A field study of winterhardiness of common wheat and triticale was established at 11 locations and repeated during three subsequent winters. The freezing tolerance of the plants was studied after controlled cold acclimation and de-acclimation using both plant survival analysis and chlorophyll fluorescence measurements. Cold deacclimation resistance was shown to be independent from cold acclimation ability. Further, cold deacclimation resistance appeared to be crucial for overwintering when deacclimation conditions occurred in the field. The shortening of uninterrupted cold acclimation may increase cold deacclimation efficiency, which could threaten plant survival during warmer winters. Measurements of chlorophyll fluorescence transient showed some differences triggered by freezing before and after deacclimation. We conclude that cold deacclimation resistance should be considered in the breeding of winter cereals and in future models of winter damage risk. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Coping with the cold: an ecological context for the abundance and distribution of rock sandpipers during winter in upper Cook Inlet, Alaska

USGS Publications Warehouse

Ruthrauff, Daniel R.; Gill, Robert E.; Tibbitts, T. Lee

2013-01-01

Shorebirds are conspicuous and abundant at high northern latitudes during spring and summer, but as seasonal conditions deteriorate, few remain during winter. To the best of our knowledge, Cook Inlet, Alaska (60.6˚ N, 151.6˚ W), is the world’s coldest site that regularly supports wintering populations of shorebirds, and it is also the most northerly nonbreeding location for shorebirds in the Pacific Basin. During the winters of 1997–2012, we conducted aerial surveys of upper Cook Inlet to document the spatial and temporal distribution and number of Rock Sandpipers (Calidris ptilocnemis) using the inlet. The average survey total was 8191 ± 6143 SD birds, and the average of each winter season’s highest single-day count was 13 603 ± 4948 SD birds. We detected only Rock Sandpipers during our surveys, essentially all of which were individuals of the nominate subspecies (C. p. ptilocnemis). Survey totals in some winters closely matched the population estimate for this subspecies, demonstrating the region’s importance as a nonbreeding resource to the subspecies. Birds were most often found at only a handful of sites in upper Cook Inlet, but shifted their distribution to more southerly locations in the inlet during periods of extreme cold. Two environmental factors allow Rock Sandpipers to inhabit Cook Inlet during winter: 1) an abundant bivalve (Macoma balthica) food source and 2) current and tidal dynamics that keep foraging substrates accessible during all but extreme periods of cold and ice accretion. C. p. ptilocnemis is a subspecies of high conservation concern for which annual winter surveys may serve as a relatively inexpensive population-monitoring tool that will also provide insight into adaptations that allow these birds to exploit high-latitude environments in winter.

Climatology of winter transition days for the contiguous USA, 1951-2007

NASA Astrophysics Data System (ADS)

Hondula, David M.; Davis, Robert E.

2011-01-01

In middle and high latitudes, climate change could impact the frequency and characteristics of frontal passages. Although transitions between air masses are significant features of the general circulation that influence human activities and other surface processes, they are much more difficult to objectively identify than single variables like temperature or even extreme events like fires, droughts, and floods. The recently developed Spatial Synoptic Classification (SSC) provides a fairly objective means of identifying frontal passages. In this research, we determine the specific meteorological patterns represented by the SSC's Transition category, a "catch-all" group that attempts to identify those days that cannot be characterized as a single, homogeneous air mass type. The result is a detailed transition climatology for the continental USA. We identify four subtypes of the Transition category based on intra-day sea level pressure change and dew point temperature change. Across the contiguous USA, most transition days are identified as cold fronts and warm fronts during the winter season. Among the two less common subtypes, transition days in which the dew point temperature and pressure both rise are more frequently observed across the western states, and days in which both variables fall are more frequently observed in coastal regions. The relative frequencies of wintertime warm and cold fronts have changed over the period 1951-2007. Relative cold front frequency has significantly increased in the Northeast and Midwest regions, and warm front frequencies have declined in the Midwest, Rocky Mountain, and Pacific Northwest regions. The overall shift toward cold fronts and away from warm fronts across the northern USA arises from a combination of an enhanced ridge over western North America and a northward shift of storm tracks throughout the mid-latitudes. These results are consistent with projections of climate change associated with elevated greenhouse gas concentrations.

Mortality risks during extreme temperature events (ETEs) using a distributed lag non-linear model

NASA Astrophysics Data System (ADS)

Allen, Michael J.; Sheridan, Scott C.

2018-01-01

This study investigates the relationship between all-cause mortality and extreme temperature events (ETEs) from 1975 to 2004. For 50 U.S. locations, these heat and cold events were defined based on location-specific thresholds of daily mean apparent temperature. Heat days were defined by a 3-day mean apparent temperature greater than the 95th percentile while extreme heat days were greater than the 97.5th percentile. Similarly, calculations for cold and extreme cold days relied upon the 5th and 2.5th percentiles. A distributed lag non-linear model assessed the relationship between mortality and ETEs for a cumulative 14-day period following exposure. Subsets for season and duration effect denote the differences between early- and late-season as well as short and long ETEs. While longer-lasting heat days resulted in elevated mortality, early season events also impacted mortality outcomes. Over the course of the summer season, heat-related risk decreased, though prolonged heat days still had a greater influence on mortality. Unlike heat, cold-related risk was greatest in more southerly locations. Risk was highest for early season cold events and decreased over the course of the winter season. Statistically, short episodes of cold showed the highest relative risk, suggesting unsettled weather conditions may have some relationship to cold-related mortality. For both heat and cold, results indicate higher risk to the more extreme thresholds. Risk values provide further insight into the role of adaptation, geographical variability, and acclimatization with respect to ETEs.

Intensity, frequency and spatial configuration of winter temperature inversions in the closed La Brevine valley, Switzerland

NASA Astrophysics Data System (ADS)

Vitasse, Yann; Klein, Geoffrey; Kirchner, James W.; Rebetez, Martine

2017-11-01

Some of the world's valleys are famous for having particularly cold microclimates. The La Brevine valley, in the Swiss Jura Mountains, holds the record for the lowest temperature ever measured in an inhabited location in Switzerland. We studied cold air pools (CAPs) in this valley during the winter of 2014-2015 using 44 temperature data loggers distributed between 1033 and 1293 m asl. Our goals were to (i) describe the climatic conditions under which CAPs form in the valley, (ii) examine the spatial configuration and the temperature structure of the CAPs and (iii) quantify how often temperature inversions occur in winter using long-term series of temperature from the valley floor. Our results show that CAPs occurred every second night, on average, during the winter of 2014-2015 and were typically formed under cloudless, windless and high-pressure conditions. Strong temperature inversions up to 28 °C were detected between the valley floor and the surrounding hills. The spatial temperature structure of the CAPs varies among the different inversion days, with the upper boundary of the cold pool generally situated at about 1150 m asl. Although mean temperatures have increased in this area over the period 1960-2015 in connection with climate change, the occurrences of extreme cold temperatures did not decrease in winter and are highly correlated with the North Atlantic Oscillation and the East Atlantic indices. This suggests that CAPs in sheltered valleys are largely decoupled from the free atmosphere temperature and will likely continue to occur in the next decades under warmer conditions.

Use of thermal inertia determined by HCMM to predict nocturnal cold prone areas in Florida

NASA Technical Reports Server (NTRS)

Allen, L. H., Jr. (Principal Investigator)

1983-01-01

Pairs of HCMM day-night thermal infrared (IR) data were selected during the 1978-79 winter to examine patterns of surface temperature and thermal inertia (TI) of peninsular Florida. The GOES and NOAA-6 thermal IR, as well as National Climatic Center temperatures and rainfall, were also used. The HCMM apparent thermal inertia (ATI) images closely corresponded to the general soil map of Florida, based on soil drainage classes. Areas with low ATI overlay well-drained soils, such as deep sands and drained organic soils, whereas with high ATI overlay areas with wetlands and bodies of water. The HCMM ATI images also corresponded well with GOES-detected winter nocturnal cold-prone areas. Use of HCMM data with Carlson's energy balance model showed both high moisture availability (MA) and high thermal inertia (TI) of wetland-type surfaces and low MA and low TI of upland, well-drained soils. Since soil areas with low TI develop higher temperatures during the day, then antecedent patterns of highest maximum daytime surface temperature can also be used to predict nocturnal cold-prone areas in Florida.

Winter is coming: hibernation reverses the outcome of sperm competition in a fly.

PubMed

Giraldo-Perez, P; Herrera, P; Campbell, A; Taylor, M L; Skeats, A; Aggio, R; Wedell, N; Price, T A R

2016-02-01

Sperm commonly compete within females to fertilize ova, but research has focused on short-term sperm storage: sperm that are maintained in a female for only a few days or weeks before use. In nature, females of many species store sperm for months or years, often during periods of environmental stress, such as cold winters. Here we examine the outcome of sperm competition in the fruit fly Drosophila pseudoobscura, simulating the conditions in which females survive winter. We mated females to two males and then stored the female for up to 120 days at 4°C. We found that the outcome of sperm competition was consistent when sperm from two males was stored for 0, 1 or 30 days, with the last male to mate fathering most of the offspring. However, when females were stored in the cold for 120 days, the last male to mate fathered less than 5% of the offspring. Moreover, when sperm were stored long term the first male fathered almost all offspring even when he carried a meiotic driving sex chromosome that drastically reduces sperm competitive success under short-term storage conditions. This suggests that long-term sperm storage can radically alter the outcome of sperm competition. © 2015 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.

Frequency of extreme daily temperatures (HadEX2) over Eurasia documented in a northern Red Sea coral oxygen isotope record during the last century

NASA Astrophysics Data System (ADS)

Ionita-Scholz, Monica; Felis, Thomas; Rimbu, Norel; Lohmann, Gerrit

2017-04-01

The potential of a bimonthly-resolved northern Red Sea coral δ18O record as an archive for the occurrence of extreme daily temperature phenomena over Eurasia during Northern Hemisphere winter is investigated for the 1901-1995 period using extreme indices provided by the HadEX2 dataset (e.g., frost days, ice days, cold nights and cold days). The coral δ18O record reflects a combined signal of temperature and salinity variations in the surface waters of the northern Red Sea, and has been previously shown to provide a proxy for atmospheric circulation changes over the Northern Hemisphere mid-latitudes at interannual to decadal time scales. Here we show, by applying composite analysis, that cooler/more arid (warmer/less arid) winter conditions in the northern Red Sea region, indicated by positive (negative) coral δ18O anomalies (January-February), are related to a strong (weak) Northern Hemisphere polar vortex and, as a consequence, to a decreased (increased) number of days characterized by very cold temperatures and frost over Scandinavia and Central Europe. This situation is associated with an increased (decreased) number of days characterized by very cold temperatures and frost over the Balkan region. The occurrence of these daily temperature extremes is modulated by the frequency of atmospheric blocking over the British Isles and Central Europe, and a shift in the direction of the North Atlantic storm tracks. Importantly, coral records provide a bimonthly to monthly resolution, compared to other high-resolution proxy records which have either an annual resolution (e.g., ice cores, varved sediments) or an annual resolution with a signal that is biased towards a specific season that in most cases is not winter (e.g., tree rings). We argue that bimonthly-resolved northern Red Sea coral δ18O records provide an archive of interannual to decadal variations in the occurrence of extreme daily temperature events over wintertime Eurasia prior to the start of instrumental observations.

A Study of School Without Schools: The Columbus, Ohio Public Schools During the Natural Gas Shortage, Winter, 1977. Volume I and Volume II, Appendices.

ERIC Educational Resources Information Center

Sanders, James R.; Stufflebeam, Daniel L.

The energy crisis, specifically a shortage of natural gas, caused by the unusually cold winter of 1977, resulted in the Columbus, Ohio, schools being closed for a month. Schools heated with gas were closed, but students met one day a week in school buildings that used coal, oil, or electricity. The educational program continued with school…

Preventing the common cold with a vitamin C supplement: a double-blind, placebo-controlled survey.

PubMed

Van Straten, Michael; Josling, Peter

2002-01-01

One hundred sixty-eight volunteers were randomized to receive a placebo or a vitamin C supplement, two tablets daily, over a 60-day period between November and February. They used a five-point scale to assess their health and recorded any common cold infections and symptoms in a daily diary. Compared with the placebo group, the active-treatment group had significantly fewer colds (37 vs 50, P<.05), fewer days challenged virally (85 vs 178), and a significantly shorter duration of severe symptoms (1.8 vs 3.1 days, P<.03). Consequently, volunteers in the active group were less likely to get a cold and recovered faster if infected. Few side effects occurred with the active treatment, and volunteers reported greatly increased satisfaction with the study supplement compared with any previous form of vitamin C. This well-tolerated vitamin C supplement may prevent the common cold and shorten the duration of symptoms. Volunteers were generally impressed by the protection afforded them during the winter months and the general acceptability of the study medication.

Factors contributing to enhanced freezing tolerance in wheat during frost hardening in the light.

PubMed

Janda, Tibor; Szalai, Gabriella; Leskó, Kornélia; Yordanova, Rusina; Apostol, Simona; Popova, Losanka Petrova

2007-06-01

The interaction between light and temperature during the development of freezing tolerance was studied in winter wheat (Triticum aestivum L. var. Mv Emese). Ten-day-old plants were cold hardened at 5 degrees C for 12 days under normal (250 micromol m(-2)s(-1)) or low light (20 micromol m(-2)s(-1)) conditions. Some of the plants were kept at 20/18 degrees C for 12 days at high light intensity (500 micromol m(-2)s(-1)), which also increased the freezing tolerance of winter wheat. The freezing survival rate, the lipid composition, the antioxidant activity, and the salicylic acid content were investigated during frost hardening. The saturation level of hexadecanoic acid decreased not only in plants hardened at low temperature, but also, to a lesser extent, in plants kept under high light irradiation at normal growth temperature. The greatest induction of the enzymes glutathione reductase (EC 1.6.4.2.) and ascorbate peroxidase (EC 1.11.1.11.) occurred when the cold treatment was carried out in normal light, but high light intensity at normal, non-hardening temperature also increased the activity of these enzymes. The catalase (EC 1.11.1.6.) activity was also higher in plants grown at high light intensity than in the controls. The greatest level of induction in the activity of the guaiacol peroxidase (EC 1.11.1.7.) enzyme occurred under cold conditions with low light. The bound ortho-hydroxy-cinnamic acid increased by up to two orders of magnitude in plants that were cold hardened in normal light. Both high light intensity and low temperature hardening caused an increase in the free and bound salicylic acid content of the leaves. This increase was most pronounced in plants that were cold treated in normal light.

The politics of atmospheric sciences: "nuclear winter" and global climate change.

PubMed

Dörries, Matthias

2011-01-01

This article, by exploring the individual and collective trajectories that led to the "nuclear winter" debate, examines what originally drew scientists on both sides of the controversy to this research. Stepping back from the day-to-day action and looking at the larger cultural and political context of nuclear winter reveals sometimes surprising commonalities among actors who found themselves on opposing sides, as well as differences within the apparently coherent TTAPS group (the theory's originators: Richard P. Turco, Owen Brian Toon, Thomas P. Ackerman, James B. Pollack, and Carl Sagan). This story foreshadows that of recent research on anthropogenic climate change, which was substantially shaped during this--apparently tangential--cold war debate of the 1980s about research on the global effects of nuclear weapons.

Analysis of the synoptic winter mortality climatology in five regions of England: Searching for evidence of weather signals.

PubMed

Paschalidou, A K; Kassomenos, P A; McGregor, G R

2017-11-15

Although heat-related mortality has received considerable research attention, the impact of cold weather on public health is less well-developed, probably due to the fact that physiological responses to cold weather can vary substantially among individuals, age groups, diseases etc., depending on a number of behavioral and physiological factors. In the current work we use the classification techniques provided by the COST-733 software to link synoptic circulation patterns with excess cold-related mortality in 5 regions of England. We conclude that, regardless of the classification scheme used, the most hazardous conditions for public health in England are associated with the prevalence of the Easterly type of weather, favoring advection of cold air from continental Europe. It is noteworthy that there has been observed little-to-no regional variation with regards to the classification results among the 5 regions, suggestive of a spatially homogenous response of mortality to the atmospheric patterns identified. In general, the 10 different groupings of days used reveal that excess winter mortality is linked with the lowest daily minimum/maximum temperatures in the area. However it is not uncommon to observe high mortality rates during days with higher, in relative terms, temperatures, when rapidly changing weather results in an increase of mortality. Such a finding confirms the complexity of cold-related mortality and highlights the importance of synoptic climatology in understanding of the phenomenon. Copyright © 2017 Elsevier B.V. All rights reserved.

A montane Mediterranean climate supports year-round photosynthesis and high forest biomass.

PubMed

Kelly, Anne E; Goulden, Michael L

2016-04-01

The mid-elevation forest of California's Sierra Nevada poses a bioclimatic paradox. Mid-elevation trees experience a montane Mediterranean climate, with near-freezing winter days and rain-free summers. The asynchrony between warmth and water input suggests low primary production, limited by photosynthetic dormancy in winter cold, and again in summer and early autumn with drought, yet this forest is characterized by tall trees and high biomass. We used eddy covariance in a mid-elevation Sierra stand to understand how winter cold and summer drought limit canopy photosynthesis and production. The trees exhibited canopy photosynthesis year-round. Trees avoided winter dormancy, and daytime CO2uptake continued despite a deep snowpack and near-freezing temperatures. Photosynthesis on sunny days continued at half of maximum rates when air temperature was 0 °C. Likewise, the vegetation avoided summer drought dormancy, and high rates of daytime CO2uptake and transpiration continued despite a 5-month period with only negligible water input. We attribute this drought avoidance to deep rooting and availability of deep soil water. Year-round photosynthesis helps explain the large biomass observed in the Sierra Nevada, and implies adaptive strategies that may contribute to the resiliency or vulnerability of Sierran vegetation to climate change. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Windowpane flounder (Scophthalmus aquosus) and winter flounder (Pseudopleuronectes americanus) responses to cold temperature extremes in a Northwest Atlantic estuary

NASA Astrophysics Data System (ADS)

Wilber, Dara H.; Clarke, Douglas G.; Alcoba, Catherine M.; Gallo, Jenine

2016-01-01

The effect of climate variability on flatfish includes not only the effects of warming on sensitive life history stages, but also impacts from more frequent or unseasonal extreme cold temperatures. Cold weather events can affect the overwintering capabilities of flatfish near their low temperature range limits. We examined the responses of two flatfish species, the thin-bodied windowpane (Scophthalmus aquosus) and cold-tolerant winter flounder (Pseudopleuronectes americanus), to variable winter temperatures in a Northwest Atlantic estuary using abundance and size data collected during a monitoring study, the Aquatic Biological Survey, conducted from 2002 to 2010. Winter and spring abundances of small (50 to 120 mm total length) juvenile windowpane were positively correlated with adult densities (spawning stock) and fall temperatures (thermal conditions experienced during post-settlement development for the fall-spawned cohort) of the previous year. Windowpane abundances in the estuary were significantly reduced and the smallest size class was nearly absent after several consecutive years with cold (minimum temperatures < 1 °C) winters. Interannual variation in winter flounder abundances was unrelated to the severity of winter temperatures. A Paulik diagram illustrates strong positive correlations between annual abundances of sequential winter flounder life history stages (egg, larval, Age-1 juvenile, and adult male) within the estuary, reflecting residency within the estuary through their first year of life. Temperature variables representing conditions during winter flounder larval and post-settlement development were not significant factors in multiple regression models exploring factors that affect juvenile abundances. Likewise, densities of predators known to consume winter flounder eggs and/or post-settlement juveniles were not significantly related to interannual variation in winter flounder juvenile abundances. Colder estuarine temperatures through the first year of life were associated with smaller Age-1 winter flounder body size. For example, Age-1 winter flounder developing under conditions that differed by 1.9 °C in mean daily water temperature, averaged 98.7 mm total length (TL) and 123.1 mm TL, for the relatively cold vs. moderate years, respectively. More frequent cold temperature extremes associated with climate variability may negatively impact the overwintering capabilities of some flatfish near their cold temperature range limits, whereas cold-tolerant species may experience reduced growth, which imparts the ecological challenges associated with smaller body size.

Winter Season Mortality: Will Climate Warming Bring Benefits?

PubMed

Kinney, Patrick L; Schwartz, Joel; Pascal, Mathilde; Petkova, Elisaveta; Tertre, Alain Le; Medina, Sylvia; Vautard, Robert

2015-06-01

Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associated with excess winter mortality across multiple cities and over multiple years within individual cities, using daily temperature and mortality data from 36 US cities (1985-2006) and 3 French cities (1971-2007). Comparing across cities, we found that excess winter mortality did not depend on seasonal temperature range, and was no lower in warmer vs. colder cities, suggesting that temperature is not a key driver of winter excess mortality. Using regression models within monthly strata, we found that variability in daily mortality within cities was not strongly influenced by winter temperature. Finally we found that inadequate control for seasonality in analyses of the effects of cold temperatures led to spuriously large assumed cold effects, and erroneous attribution of winter mortality to cold temperatures. Our findings suggest that reductions in cold-related mortality under warming climate may be much smaller than some have assumed. This should be of interest to researchers and policy makers concerned with projecting future health effects of climate change and developing relevant adaptation strategies.

Winter season mortality: will climate warming bring benefits?

NASA Astrophysics Data System (ADS)

Kinney, Patrick L.; Schwartz, Joel; Pascal, Mathilde; Petkova, Elisaveta; Le Tertre, Alain; Medina, Sylvia; Vautard, Robert

2015-06-01

Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associated with excess winter mortality across multiple cities and over multiple years within individual cities, using daily temperature and mortality data from 36 US cities (1985-2006) and 3 French cities (1971-2007). Comparing across cities, we found that excess winter mortality did not depend on seasonal temperature range, and was no lower in warmer vs. colder cities, suggesting that temperature is not a key driver of winter excess mortality. Using regression models within monthly strata, we found that variability in daily mortality within cities was not strongly influenced by winter temperature. Finally we found that inadequate control for seasonality in analyses of the effects of cold temperatures led to spuriously large assumed cold effects, and erroneous attribution of winter mortality to cold temperatures. Our findings suggest that reductions in cold-related mortality under warming climate may be much smaller than some have assumed. This should be of interest to researchers and policy makers concerned with projecting future health effects of climate change and developing relevant adaptation strategies.

RATIONAL DETERMINATION METHOD OF PROBABLE FREEZING INDEX FOR n-YEARS CONSIDERING THE REGIONAL CHARACTERISTICS

NASA Astrophysics Data System (ADS)

Kawabata, Shinichiro; Hayashi, Keiji; Kameyama, Shuichi

This paper investigates a method for ob taining the probable freezing index for n -years from past frostaction damage and meteorological data. From investigati on of Japanese cold winter data from the areas of Hokkaido, Tohoku and south of Tohoku, it was found that the extent of cold winter had regularity by location south or north. Also, after obtaining return periods of cold winters by area, obvious regional characteristics were found. Mild winters are rare in Hokkaido. However, it was clarified that when Hokkaido had cold winters, its size increased. It wa s effective to determine the probable freezing indices as 20-, 15- and 10-year return periods for Hokkaido, Tohoku and south of Tohoku, respectively.

Effect of winter cold duration on spring phenology of the orange tip butterfly, Anthocharis cardamines.

PubMed

Stålhandske, Sandra; Lehmann, Philipp; Pruisscher, Peter; Leimar, Olof

2015-12-01

The effect of spring temperature on spring phenology is well understood in a wide range of taxa. However, studies on how winter conditions may affect spring phenology are underrepresented. Previous work on Anthocharis cardamines (orange tip butterfly) has shown population-specific reaction norms of spring development in relation to spring temperature and a speeding up of post-winter development with longer winter durations. In this experiment, we examined the effects of a greater and ecologically relevant range of winter durations on post-winter pupal development of A. cardamines of two populations from the United Kingdom and two from Sweden. By analyzing pupal weight loss and metabolic rate, we were able to separate the overall post-winter pupal development into diapause duration and post-diapause development. We found differences in the duration of cold needed to break diapause among populations, with the southern UK population requiring a shorter duration than the other populations. We also found that the overall post-winter pupal development time, following removal from winter cold, was negatively related to cold duration, through a combined effect of cold duration on diapause duration and on post-diapause development time. Longer cold durations also lead to higher population synchrony in hatching. For current winter durations in the field, the A. cardamines population of southern UK could have a reduced development rate and lower synchrony in emergence because of short winters. With future climate change, this might become an issue also for other populations. Differences in winter conditions in the field among these four populations are large enough to have driven local adaptation of characteristics controlling spring phenology in response to winter duration. The observed phenology of these populations depends on a combination of winter and spring temperatures; thus, both must be taken into account for accurate predictions of phenology.

Change in abundance of pacific brant wintering in alaska: evidence of a climate warming effect?

USGS Publications Warehouse

Ward, David H.; Dau, Christian P.; Tibbitts, T. Lee; Sedinger, James S.; Anderson, Betty A.; Hines, James E.

2009-01-01

Winter distribution of Pacific Flyway brant (Branta bernicla nigricans) has shifted northward from lowtemperate areas to sub-Arctic areas over the last 42 years. We assessed the winter abundance and distribution of brant in Alaska to evaluate whether climate warming may be contributing to positive trends in the most northern of the wintering populations. Mean surface air temperatures during winter at the end of the Alaska Peninsula increased about 1??C between 1963 and 2004, resulting in a 23% reduction in freezing degree days and a 34% decline in the number of days when ice cover prevents birds from accessing food resources. Trends in the wintering population fluctuated with states of the Pacific Decadal Oscillation, increasing during positive (warm) phases and decreasing during negative (cold) phases, and this correlation provides support for the hypothesis that growth in the wintering population of brant in Alaska is linked to climate warming. The size of the wintering population was negatively correlated with the number of days of strong northwesterly winds in November, which suggests that the occurrence of tailwinds favorable for migration before the onset of winter was a key factor in whether brant migrated from Alaska or remained there during winter. Winter distribution of brant on the Alaska Peninsula was highly variable and influenced by ice cover, particularly at the heavily used Izembek Lagoon. Observations of previously marked brant indicated that the Alaska wintering population was composed primarily of birds originating from Arctic breeding colonies that appear to be growing. Numbers of brant in Alaska during winter will likely increase as temperatures rise and ice cover decreases at high latitudes in response to climate warming. ?? The Arctic Institute of North America.

Livable Winter Cities--Leisure Attitudes and Activities.

ERIC Educational Resources Information Center

Neal, Larry; Coles, Roger, Ed.

1989-01-01

The nine articles included in this feature emphasize how leisure, recreation, health and physical activities make winter cities more livable. Specific topics include techniques for teaching about cold weather safety and cold related injuries, Arctic Winter Games, and results of a study on winter recreation in large North American communities. (IAH)

Lower Stratospheric Temperature Differences Between Meteorological Analyses in two cold Arctic Winters and their Impact on Polar Processing Studies

NASA Technical Reports Server (NTRS)

Manney, Gloria L.; Sabutis, Joseph L.; Pawson, Steven; Santee, Michelle L.; Naujokat, Barbara; Swinbank, Richard; Gelman, Melvyn E.; Ebisuzaki, Wesley; Atlas, Robert (Technical Monitor)

2001-01-01

A quantitative intercomparison of six meteorological analyses is presented for the cold 1999-2000 and 1995-1996 Arctic winters. The impacts of using different analyzed temperatures in calculations of polar stratospheric cloud (PSC) formation potential, and of different winds in idealized trajectory-based temperature histories, are substantial. The area with temperatures below a PSC formation threshold commonly varies by approximately 25% among the analyses, with differences of over 50% at some times/locations. Freie University at Berlin analyses are often colder than others at T is less than or approximately 205 K. Biases between analyses vary from year to year; in January 2000. U.K. Met Office analyses were coldest and National Centers for Environmental Prediction (NCEP) analyses warmest. while NCEP analyses were usually coldest in 1995-1996 and Met Office or NCEP[National Center for Atmospheric Research Reanalysis (REAN) warmest. European Centre for Medium Range Weather Forecasting (ECMWF) temperatures agreed better with other analyses in 1999-2000, after improvements in the assimilation model. than in 1995-1996. Case-studies of temperature histories show substantial differences using Met Office, NCEP, REAN and NASA Data Assimilation Office (DAO) analyses. In January 2000 (when a large cold region was centered in the polar vortex), qualitatively similar results were obtained for all analyses. However, in February 2000 (a much warmer period) and in January and February 1996 (comparably cold to January 2000 but with large cold regions near the polar vortex edge), distributions of "potential PSC lifetimes" and total time spent below a PSC formation threshold varied significantly among the analyses. Largest peaks in "PSC lifetime" distributions in January 2000 were at 4-6 and 11-14 days. while in the 1996 periods, they were at 1-3 days. Thus different meteorological conditions in comparably cold winters had a large impact on expectations for PSC formation and on the discrepancies between different meteorological analyses. Met Office. NCEP, REAN, ECMWF and DAO analyses are commonly used for trajectory calculations and in chemical transport models; the choice of which analysis to use can strongly influence the results of such studies.

Comparison of subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers in Japan.

PubMed

Inaba, Ryoichi; Kurokawa, Junichi; Mirbod, Seyed Mohammad

2009-07-01

To help making comfortable workplaces and to prevent health disorders induced by the exposure to moderate cold in two different groups of out-door workers, we conducted a survey to compare subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers. The subjects of this study were 98 male traffic control workers and 149 male workers engaged in building construction. Work loads of traffic control workers and construction workers were estimated at RMR1-2 and RMR2-4, respectively. All subjects were asked to complete a self-administered questionnaire covering age, occupational career, working figure, present illness, past history of diseases, individual preventive measures to the cold, subjective symptoms in the winter (43 items) and subjective symptoms occurred during daytime working in the winter (6 items). In two parts of the construction workplaces (the place where a morning assembly was held and on the 7th floor of the construction site) dry bulb, wet bulb and globe temperatures were measured in January. Windchill Index (kcal/cm,(2) x h) was calculated by the measured dry bulb temperature and wind velocity. Mean values of dry bulb temperature between 9:00 and 16:30 in the place where a morning assembly was held for three days were between 4.8 +/- 1.2 degrees C at 9:00 am and 9.3 +/- 1.1 degrees C at noon. Mean values of Windchill Index in the place where a morning assembly was held were between 490.8+/-23.9 kcal/cm(2) x h at 9:30 am and 608.2+/-47.3 kcal/cm(2) x h at 2:30 pm. Occupational career, monthly working days, daily working hours, one way commuting hours, and daily smoking numbers of the traffic control workers were significantly shorter than the construction workers (p<0.01). There were no significant differences in the prevalence of chillness in the arms and legs between the traffic control workers (5.1%) and the construction workers (0.7%). Prevalence of wearing a warm underwear, body warmer, warm trousers, underpants, warm socks, shoe warmer and muffler in the traffic control workers were significantly higher than the construction workers. The subjective symptoms in winter complained most frequently were shoulder stiffness (51.0%), finger cold sensation (50.0%) and neck stiffness (48.0%) in the traffic control workers, and were easy to get fatigued (49.0%), lumbago (48.3%) and finger cold sensation (47.7%) in the construction workers. On the basis of the results obtained, it is clearly shown that the two groups are at the risk of disorders due to their working environment. Therefore, these workers are needed to undergo occupational health programs for prevention of cold exposure disorders. Applications of preventive countermeasures for both groups are discussed.

Decreasing but still significant facilitation effect of cold-season macrophytes on wetlands purification function during cold winter.

PubMed

Zou, Xiangxu; Zhang, Hui; Zuo, Jie; Wang, Penghe; Zhao, Dehua; An, Shuqing

2016-06-01

To identify the facilitation effect of a cool-season aquatic macrophyte (FEam) for use in effluent purification via constructed floating wetlands (CFWs) and to determine the possible pathways used during a winter period with an average temperature of less than 5 °C, pilot-scale CFWs were planted with the cold-season macrophyte Oenanthe clecumbens and were operated as batch systems. Although some leaves withered, the roots retained relatively high levels of activity during the winter, which had average air and water temperatures of 3.63 and 5.04 °C, respectively. The N and P removal efficiencies in CFWs decreased significantly in winter relative to those in late autumn. The presence of cool-season plants resulted in significant improvements in N and P removal, with a FEam of 15.23-25.86% in winter. Microbial N removal accounted for 71.57% of the total N removed in winter, and the decrease in plant uptake was the dominant factor in the wintertime decrease in N removal relative to that in late autumn. These results demonstrate the importance of cold-season plants in CFWs for the treatment of secondary effluent during cold winters.

Mitochondrial energy-dissipating systems (alternative oxidase, uncoupling proteins, and external NADH dehydrogenase) are involved in development of frost-resistance of winter wheat seedlings.

PubMed

Grabelnych, O I; Borovik, O A; Tauson, E L; Pobezhimova, T P; Katyshev, A I; Pavlovskaya, N S; Koroleva, N A; Lyubushkina, I V; Bashmakov, V Yu; Popov, V N; Borovskii, G B; Voinikov, V K

2014-06-01

Gene expression, protein synthesis, and activities of alternative oxidase (AOX), uncoupling proteins (UCP), adenine nucleotide translocator (ANT), and non-coupled NAD(P)H dehydrogenases (NDex, NDPex, and NDin) were studied in shoots of etiolated winter wheat (Triticum aestivum L.) seedlings after exposure to hardening low positive (2°C for 7 days) and freezing (-2°C for 2 days) temperatures. The cold hardening efficiently increased frost-resistance of the seedlings and decreased the generation of reactive oxygen species (ROS) during further cold shock. Functioning of mitochondrial energy-dissipating systems can represent a mechanism responsible for the decrease in ROS under these conditions. These systems are different in their response to the action of the hardening low positive and freezing temperatures. The functioning of the first system causes induction of AOX and UCP synthesis associated with an increase in electron transfer via AOX in the mitochondrial respiratory chain and also with an increase in the sensitivity of mitochondrial non-phosphorylating respiration to linoleic and palmitic acids. The increase in electron transfer via AOX upon exposure of seedlings to hardening freezing temperature is associated with retention of a high activity of NDex. It seems that NDex but not the NDPex and NDin can play an important role in maintaining the functional state of mitochondria in heterotrophic tissues of plants under the influence of freezing temperatures. The involvement of the mitochondrial energy-dissipating systems and their possible physiological role in the adaptation of winter crops to cold and frost are discussed.

Reproductive arrest and stress resistance in winter-acclimated Drosophila suzukii.

PubMed

Toxopeus, Jantina; Jakobs, Ruth; Ferguson, Laura V; Gariepy, Tara D; Sinclair, Brent J

2016-06-01

Overwintering insects must survive the multiple-stress environment of winter, which includes low temperatures, reduced food and water availability, and cold-active pathogens. Many insects overwinter in diapause, a developmental arrest associated with high stress tolerance. Drosophila suzukii (Diptera: Drosophilidae), spotted wing drosophila, is an invasive agricultural pest worldwide. Its ability to overwinter and therefore establish in temperate regions could have severe implications for fruit crop industries. We demonstrate here that laboratory populations of Canadian D. suzukii larvae reared under short-day, low temperature, conditions develop into dark 'winter morph' adults similar to those reported globally from field captures, and observed by us in southern Ontario, Canada. These winter-acclimated adults have delayed reproductive maturity, enhanced cold tolerance, and can remain active at low temperatures, although they do not have the increased desiccation tolerance or survival of fungal pathogen challenges that might be expected from a more heavily melanised cuticle. Winter-acclimated female D. suzukii have underdeveloped ovaries and altered transcript levels of several genes associated with reproduction and stress. While superficially indicative of reproductive diapause, the delayed reproductive maturity of winter-acclimated D. suzukii appears to be temperature-dependent, not regulated by photoperiod, and is thus unlikely to be 'true' diapause. The traits of this 'winter morph', however, likely facilitate overwintering in southern Canada, and have probably contributed to the global success of this fly as an invasive species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantification and assessment of heat and cold waves in Novi Sad, Northern Serbia

NASA Astrophysics Data System (ADS)

Basarin, Biljana; Lukić, Tin; Matzarakis, Andreas

2016-01-01

Physiologically equivalent temperature (PET) has been applied to the analysis of heat and cold waves and human thermal conditions in Novi Sad, Serbia. A series of daily minimum and maximum air temperature, relative humidity, wind, and cloud cover was used to calculate PET for the investigated period 1949-2012. The heat and cold wave analysis was carried out on days with PET values exceeding defined thresholds. Additionally, the acclimatization approach was introduced to evaluate human adaptation to interannual thermal perception. Trend analysis has revealed the presence of increasing trend in summer PET anomalies, number of days above defined threshold, number of heat waves, and average duration of heat waves per year since 1981. Moreover, winter PET anomaly as well as the number of days below certain threshold and number of cold waves per year until 1980 was decreasing, but the decrease was not statistically significant. The highest number of heat waves during summer was registered in the last two decades, but also in the first decade of the investigated period. On the other hand, the number of cold waves during six decades is quite similar and the differences are very small.

Quantification and assessment of heat and cold waves in Novi Sad, Northern Serbia.

PubMed

Basarin, Biljana; Lukić, Tin; Matzarakis, Andreas

2016-01-01

Physiologically equivalent temperature (PET) has been applied to the analysis of heat and cold waves and human thermal conditions in Novi Sad, Serbia. A series of daily minimum and maximum air temperature, relative humidity, wind, and cloud cover was used to calculate PET for the investigated period 1949-2012. The heat and cold wave analysis was carried out on days with PET values exceeding defined thresholds. Additionally, the acclimatization approach was introduced to evaluate human adaptation to interannual thermal perception. Trend analysis has revealed the presence of increasing trend in summer PET anomalies, number of days above defined threshold, number of heat waves, and average duration of heat waves per year since 1981. Moreover, winter PET anomaly as well as the number of days below certain threshold and number of cold waves per year until 1980 was decreasing, but the decrease was not statistically significant. The highest number of heat waves during summer was registered in the last two decades, but also in the first decade of the investigated period. On the other hand, the number of cold waves during six decades is quite similar and the differences are very small.

Estimating and projecting the effect of cold waves on mortality in 209 US cities.

PubMed

Wang, Yan; Shi, Liuhua; Zanobetti, Antonella; Schwartz, Joel D

2016-09-01

The frequency, duration, and intensity of cold waves are expected to decrease in the near future under the changing climate. However, there is a lack of understanding on future mortality related to cold waves. The present study conducted a large-scale national projection to estimate future mortality attributable to cold waves during 1960-2050 in 209 US cities. Cold waves were defined as two, three, or at least four consecutive days with daily temperature lower than the 5th percentile of temperatures in each city. The lingering period of a cold wave was defined as the non-cold wave days within seven days following that cold wave period. First, with 168million residents in 209 US cities during 1962-2006, we fitted over-dispersed Poisson regressions to estimate the immediate and lingering effects of cold waves on mortality and tested if the associations were modified by the duration of cold waves, the intensity of cold waves, and mean winter temperature (MWT). Then we projected future mortality related to cold waves using 20 downscaled climate models. Here we show that the cold waves (both immediate and lingering) were associated with an increased but small risk of mortality. The associations varied substantially across climate regions. The risk increased with the duration and intensity of cold waves but decreased with MWT. The projected mortality related to cold waves would decrease from 1960 to 2050. Such a decrease, however, is small and may not be able to offset the potential increase in heat-related deaths if the adaptation to heat is not adequate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Inability of Ceratitis capitata (Diptera: Tephritidae) to overwinter in the Judean hills.

PubMed

Israely, Nimrod; Ritte, Uzi; Oman, Samuel D

2004-02-01

The overwintering potential of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), in cold winter areas within its northern distribution is a key element in understanding its ecology. Recent studies have suggested that although originating in tropical Africa, the fly has become adapted to the cold weather that prevails within its northernmost areas of distribution. We address the question of whether the Mediterranean fruit fly has expanded its overwintering range to include the mountains of central Israel. Doing so would imply that the fly has developed either a behavioral or a physiological mechanism to cope with low temperature and/or damp conditions in combination with cold. We monitored adult populations year round, sampling fruit, calculating expected emergence days for overwintering flies, and studying adults captured within dense and sparse apple orchards. We also performed several manipulative experiments to study preimago ability to survive the winter under natural or seminatural conditions. The study was conducted in the central mountains of Israel at 700-m altitude from 1994 to 2003. Comparison experiments also were conducted at 400 m and at sea level. Our results show 1) no adults captured during the winter and spring, 2) an absence of new infestations during the winter and spring, and 3) inability of preimago stages to overwinter in the central mountains of Israel. Thus, we conclude that the fly does not overwinter in the central mountains of Israel. We discuss the ecological and applied significance of our findings.

Phenology and drivers of the winter-spring phytoplankton bloom in the open Black Sea: The application of Sverdrup's hypothesis and its refinements

NASA Astrophysics Data System (ADS)

Mikaelyan, Alexander S.; Chasovnikov, Valeriy K.; Kubryakov, Arseny A.; Stanichny, Sergey V.

2017-02-01

The phenology of the winter-spring phytoplankton bloom in the Black Sea was investigated on the basis of the satellite-derived chlorophyll concentration (Chl) for the recent 18-year period. Data for the 8-day Chl were analysed, together with changes in the nutrient concentration, sea surface temperature (SST), photosynthetically available radiation, wind velocity and duration. Based on Sverdrup's Critical Depth hypothesis and its recent refinements, the Pulsing-Bloom hypothesis was proposed for the highly stratified waters of the Black Sea. This hypothesis relates the biological response to physical forcing and chemical fluxes to the photic zone and predicts the pulsing growth of phytoplankton and different patterns of phytoplankton changes in the upper layer in winter-spring during cold and regular years. The hypothesis was supported by Chl dynamics and several Chl peaks were observed during winter-spring. Normally, the highest Chl occurred in winter and a spring peak was absent, whereas in cold years, a relatively low Chl in winter was followed by a spring bloom. These events were observed only in 15% of cases and the magnitude of the bloom was associated with the intensity of winter convection that was revealed by the negative inter-annual correlation between the March Chl and the February SST. In contrast, the February Chl was positively correlated with the SST. The proposed hypothesis provides an explanation of this phenomenon on the basis of an alternation between the low-turbulence and deep-mixing regimes. This mechanism was confirmed by the positive relationships between Chl and the duration of light wind during the current period and strong wind in the previous period. Inorganic nitrogen was depleted disproportionately during the winter-spring, whereas the phosphate concentration remained relatively high. Following a cold winter, the highest phosphate concentration and extremely low nitrogen-to-phosphorus molar ratios (2) were observed in the upper 25-m layer in late spring. The regular absence of spring blooms might represent one of the consequences of the regional climate change.

Transcriptional profiles of the annual growth cycle in Populus deltoides.

PubMed

Park, Sunchung; Keathley, Daniel E; Han, Kyung-Hwan

2008-03-01

Cycling between vegetative growth and dormancy is an important adaptive mechanism in temperate woody plants. To gain insights into the underlying molecular mechanisms, we carried out global transcription analyses on stem samples from poplar (Populus deltoides Bartr. ex Marsh.) trees grown in the field and in controlled environments. Among seasonal changes in the transcriptome, up-regulation of defense-related genes predominated in early winter, whereas signaling-related genes were up-regulated during late winter. Cluster analysis of the differentially expressed genes showed that plants regulated seasonal growth by integrating environmental factors with development. Short day lengths induced some cold-associated genes without concomitant low temperature exposure, and enhanced the expression of some genes when combined with low temperature exposure. These mechanisms appear to maintain closer synchrony between cold hardiness and climate than would be achieved through responses to temperature alone.

Damage to southern Michigan conifers during the winter of 1976-77

Treesearch

Jonathan W. Wright; Donald DeHayes; Walter A. Lemmien

1977-01-01

In southern Michigan, the winter of 1976-1977 was marked by unseasonably cold weather in early December, prolonged cold weather in December and January, severe drought at the onset of cold weather, and by higher than average absolute minimum temperatures. Damage, presumably from the early December cold weather, was severe to southern seedlots of ponderosa pine,...

Weakening of the Stratospheric Polar Vortex by Arctic Sea-Ice Loss

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Baek-Min; Son, Seok-Woo; Min, Seung-Ki

2014-09-02

Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea ice, the mechanism that links sea ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea ice cover during early winter months (November-December), especially over themore » Barents-Kara seas, enhance the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January- February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.« less

Intraseasonal Cold Air Outbreak over East Asia and the preceding atmospheric condition over the Barents-Kara Sea

NASA Astrophysics Data System (ADS)

Hori, M. E.; Inoue, J.

2011-12-01

Frequent occurrence of cold air outbreak is a dominant feature of the East Asian winter monsoon. A contributing factor for the this cold air outbreak is the role of stationary Rossby waves over the Eurasian continent which intensifies the surface Siberian High and the accompanying cold air outflow. Reduced sea ice and increase in turbulence heat flux is hypothesized as a source of such stationary waves (Honda et al. 2009). In particular, the winter of 2009/2010 saw a strong correlation of high pressure anomaly over the Barents/Kara sea and the following cold air buildup over the Eurasian continent and its advection towards East Asia (Hori et al. 2011). The lag correlation of surface temperature over Japan and the 850hPa geopotential height shows a cyclonic anomaly appearing over the Barents/Kara sea which creates a cold air advection over the Eurasian continent. The pressure anomaly subsequently shifted westward to mature into a blocking high which created a wave- train pattern downstream advecting the cold air buildup eastward toward East Asia and Japan (Fig1). We further examine this mechanism for other years including the 2005/2006, 2010/2011 winter and other winters with extreme cold air outbreaks. Overall, the existence of an anticyclonic anomaly over the Barents/Kara sea correlated well with the seasonal dominance of cold air over the Eurasian continent thereby creating a contrast of a warm Arctic and cold Eurasian continent.In the intraseasonal timescale, the existence of this anticyclone corresponds to a persisting atmospheric blocking in the high latitudes. In the presentation, we address the underlying chain of events leading up to a strong cold air outbreak over East Asia from an atmosphere - sea ice - land surafce interaction point of view for paritular cold winter years.

Time-Course of Cause-Specific Hospital Admissions During Snowstorms: An Analysis of Electronic Medical Records From Major Hospitals in Boston, Massachusetts

PubMed Central

Bobb, Jennifer F.; Ho, Kalon K. L.; Yeh, Robert W.; Harrington, Lori; Zai, Adrian; Liao, Katherine P.; Dominici, Francesca

2017-01-01

Abstract With global climate change, more frequent severe snowstorms are expected; however, evidence regarding their health effects is very limited. We gathered detailed medical records on hospital admissions (n = 433,037 admissions) from the 4 largest hospitals in Boston, Massachusetts, during the winters of 2010–2015. We estimated the percentage increase in hospitalizations for cardiovascular and cold-related diseases, falls, and injuries on the day of and for 6 days after a day with low (0.05–5.0 inches), moderate (5.1–10.0 inches), or high (>10.0 inches) snowfall using distributed lag regression models. We found that cardiovascular disease admissions decreased by 32% on high snowfall days (relative risk (RR) = 0.68, 95% confidence interval (CI): 0.54, 0.85) but increased by 23% 2 days after (RR = 1.23, 95% CI: 1.01, 1.49); cold-related admissions increased by 3.7% on high snowfall days (RR = 3.7, 95% CI: 1.6, 8.6) and remained high for 5 days after; and admissions for falls increased by 18% on average in the 6 days after a moderate snowfall day (RR = 1.18, 95% CI: 1.09, 1.27). We did not find a higher risk of hospitalizations for injuries. To our knowledge, this is the first study in which the time course of hospitalizations during and immediately after snowfall days has been examined. These findings can be translated into interventions that prevent hospitalizations and protect public health during harsh winter conditions. PMID:28137774

Severe European winters in a secular perspective

NASA Astrophysics Data System (ADS)

Hoy, Andreas; Hänsel, Stephanie

2017-04-01

Temperature conditions during the winter time are substantially shaped by a strong year-to-year variability. European winters since the late 1980s - compared to previous decades and centuries - were mainly characterised by a high temperature level, including recent record-warm winters. Yet, comparably cold winters and severe cold spells still occur nowadays, like recently observed from 2009 to 2013 and in early 2017. Central England experienced its second coldest December since start of observations more than 350 years ago in 2010, and some of the lowest temperatures ever measured in northern Europe (below -50 °C in Lapland) were recorded in January 1999. Analysing thermal characteristics and spatial distribution of severe (historical) winters - using early instrumental data - helps expanding and consolidating our knowledge of past weather extremes. This contribution presents efforts towards this direction. We focus on a) compiling and assessing a very long-term instrumental, spatially widespread and well-distributed, high-quality meteorological data set to b) investigate very cold winter temperatures in Europe from early measurements until today. In a first step, we analyse the longest available time series of monthly temperature averages within Europe. Our dataset extends from the Nordic countries up to the Mediterranean and from the British Isles up to Russia. We utilise as much as possible homogenised times series in order to ensure reliable results. Homogenised data derive from the NORDHOM (Scandinavia) and HISTALP (greater alpine region) datasets or were obtained from national weather services and universities. Other (not specifically homogenised) data were derived from the ECA&D dataset or national institutions. The employed time series often start already during the 18th century, with Paris & Central England being the longest datasets (from 1659). In a second step, daily temperature averages are involved. Only some of those series are homogenised, but those available are sufficiently distributed throughout Europe to ensure reliable results. Furthermore, the comparably dense network of long-term observations allows an appropriate quality checking within the network. Additionally, the large collective of homogenised monthly data enables assessing the quality of many daily series. Daily data are used to sum up negative values for the respective winter periods to create times series of "cold summations", which are a good indicator for the severeness of winters in most parts of Europe. Additionally, days below certain thresholds may be counted or summed up. Future work will include daily minimum and maximum temperatures, allowing calculating and applying an extensive set of climate indices, refining the work presented here.

Scratching the Surface

ERIC Educational Resources Information Center

Bartholomeo, Linda

2011-01-01

The drab, cold days of winter were not helping to motivate the author's painting students. Still-life work appeared forced, tight, and overworked. A downed white birch in her front yard provided the author a resource and inspiration. In this article, students do some timed gestural drawings of still life using sticks as paintbrushes. (Contains 1…

A randomized controlled trial of chelated zinc for prevention of the common cold in Thai school children.

PubMed

Rerksuppaphol, Sanguansak; Rerksuppaphol, Lakkana

2013-08-01

The common cold is responsible for the largest proportion of school and work absenteeism and is a huge economic burden. None of the currently available interventions is clearly effective for prevention or treatment. To assess the efficacy of 15-mg chelated zinc (zinc bis-glycinate) given once a day for 3 months during the winter season to healthy school children aged 8-13 years to prevent symptoms of the common cold. In a double-blind randomized controlled trial, zinc bis-glycinate 15 mg or matching placebo once a day for 3 months was administered to healthy school children aged 8-13 years. Primary outcomes were any symptom of cold (fever, cough, rhinorrhoea) during the study period, and secondary outcomes were vomiting, diarrhoea, use of antibiotics, school absence for any reason, school absence because of a cold and duration of all symptoms. Of 50 children in each group, 42 (84%) in the zinc group and 41 (82%) in the placebo group (P = 1.00) developed at least one symptom of a cold. There was no difference in the incidence of fever, cough, rhinorrhoea, school absence and school absence related to the common cold compared with children in the placebo group. However, duration of cough [median (IQR) 1.0 (0.0-6.0) vs 6.0 (0.0-13.3) days], rhinorrhoea [median (IQR) 2.0 (0.0-7.0) vs 5.5 (1.0-15.3) days] and the frequency of having two or more symptoms of the common cold [median (IQR) 0.0 (0.0-1.0) vs 1.0 (0.0-5.3) days] were reduced significantly in the intervention group (P<0.01). Zinc bis-glycinate given in a dose of 15 mg once a day for 3 months failed to reduce the incidence of the common cold in 8 to 13-year-old school children, but decreased the number of days on which children suffered from cough, rhinorrhoea and the likelihood of having two or more symptoms of the common cold.

A possible role for flowering locus T-encoding genes in interpreting environmental and internal cues affecting olive (Olea europaea L.) flower induction.

PubMed

Haberman, Amnon; Bakhshian, Ortal; Cerezo-Medina, Sergio; Paltiel, Judith; Adler, Chen; Ben-Ari, Giora; Mercado, Jose Angel; Pliego-Alfaro, Fernando; Lavee, Shimon; Samach, Alon

2017-08-01

Olive (Olea europaea L.) inflorescences, formed in lateral buds, flower in spring. However, there is some debate regarding time of flower induction and inflorescence initiation. Olive juvenility and seasonality of flowering were altered by overexpressing genes encoding flowering locus T (FT). OeFT1 and OeFT2 caused early flowering under short days when expressed in Arabidopsis. Expression of OeFT1/2 in olive leaves and OeFT2 in buds increased in winter, while initiation of inflorescences occurred i n late winter. Trees exposed to an artificial warm winter expressed low levels of OeFT1/2 in leaves and did not flower. Olive flower induction thus seems to be mediated by an increase in FT levels in response to cold winters. Olive flowering is dependent on additional internal factors. It was severely reduced in trees that carried a heavy fruit load the previous season (harvested in November) and in trees without fruit to which cold temperatures were artificially applied in summer. Expression analysis suggested that these internal factors work either by reducing the increase in OeFT1/2 expression or through putative flowering repressors such as TFL1. With expected warmer winters, future consumption of olive oil, as part of a healthy Mediterranean diet, should benefit from better understanding these factors. © 2017 John Wiley & Sons Ltd.

Genes critical for the induction of cold acclimation in wheat (Triticum aestivum L.)

USDA-ARS?s Scientific Manuscript database

Phenotypic studies have shown that cold acclimation in wheat and its relatives start at different temperatures. To gain insight into the underlying mechanisms that regulate the induction of cold-acclimation process in cereals we compared the expression of genes in winter-habit (winter Norstar and w...

Is "Warm Arctic, Cold Continent" A Fingerprint Pattern of Climate Change?

NASA Astrophysics Data System (ADS)

Hoerling, M. P.; Sun, L.; Perlwitz, J.

2015-12-01

Cold winters and cold waves have recently occurred in Europe, central Asia and the Midwest to eastern United States, even as global mean temperatures set record highs and Arctic amplification of surface warming continued. Since 1979, Central Asia winter temperatures have in fact declined. Conjecture has it that more cold extremes over the mid-latitude continents should occur due to global warming and the impacts of Arctic sea ice loss. A Northern Hemisphere temperature signal termed the "Warm Arctic, Cold Continent" pattern has thus been surmised. Here we use a multi-model approach to test the hypothesis that such a pattern is indeed symptomatic of climate change. Diagnosis of a large model ensemble of historical climate simulations shows some individual realizations to yield cooling trends over Central Asia, but importantly the vast majority show warming. The observed cooling has thus likely been a low probability state of internal variability, not a fingerprint of forced climate change. We show that daily temperature variations over continents decline in winter due to global warming, and cold waves become less likely. This is partly related to diminution of Arctic cold air reservoirs due to warming-induced sea ice loss. Nonetheless, we find some evidence and present a physical basis that Arctic sea ice loss alone can induce a winter cooling over Central Asia, though with a magnitude that is appreciably smaller than the overall radiative-forced warming signal. Our results support the argument that recent cooling trends over central Asia, and cold extreme events over the winter continents, have principally resulted from atmospheric internal variability and have been neither a forced response to Arctic seas ice loss nor a symptom of global warming. The paradigm of climate change is thus better expressed as "Warm Arctic, Warm Continent" for the NH winter.

The role of Xylella fastidiosa cold shock proteins in Pierce’s disease of grapes

USDA-ARS?s Scientific Manuscript database

Pierce’s disease of grapevine, caused by the bacterial pathogen Xylella fastidiosa (Xf) is limited to warmer climates, and plant infection can be eliminated by cold winter conditions. Milder winters can increase the likelihood of pathogen persistence from one growing season to the next. Cold adaptat...

Can Winter-Active Bumblebees Survive the Cold? Assessing the Cold Tolerance of Bombus terrestris audax and the Effects of Pollen Feeding

PubMed Central

Owen, Emily L.; Bale, Jeffrey S.; Hayward, Scott A. L.

2013-01-01

There is now considerable evidence that climate change is disrupting the phenology of key pollinator species. The recently reported UK winter activity of the bumblebee Bombus terrestris brings a novel set of thermal challenges to bumblebee workers that would typically only be exposed to summer conditions. Here we assess the ability of workers to survive acute and chronic cold stress (via lower lethal temperatures and lower lethal times at 0°C), the capacity for rapid cold hardening (RCH) and the influence of diet (pollen versus nectar consumption) on supercooling points (SCP). Comparisons are made with chronic cold stress indices and SCPs in queen bumblebees. Results showed worker bees were able to survive acute temperatures likely to be experienced in a mild winter, with queens significantly more tolerant to chronic cold temperature stress. The first evidence of RCH in any Hymenoptera is shown. In addition, dietary manipulation indicated the consumption of pollen significantly increased SCP temperature. These results are discussed in the light of winter active bumblebees and climate change. PMID:24224036

Beef cattle body temperature during climatic stress: a genome-wide association study.

PubMed

Howard, Jeremy T; Kachman, Stephen D; Snelling, Warren M; Pollak, E John; Ciobanu, Daniel C; Kuehn, Larry A; Spangler, Matthew L

2014-09-01

Cattle are reared in diverse environments and collecting phenotypic body temperature (BT) measurements to characterize BT variation across diverse environments is difficult and expensive. To better understand the genetic basis of BT regulation, a genome-wide association study was conducted utilizing crossbred steers and heifers totaling 239 animals of unknown pedigree and breed fraction. During predicted extreme heat and cold stress events, hourly tympanic and vaginal BT devices were placed in steers and heifers, respectively. Individuals were genotyped with the BovineSNP50K_v2 assay and data analyzed using Bayesian models for area under the curve (AUC), a measure of BT over time, using hourly BT observations summed across 5-days (AUC summer 5-day (AUCS5D) and AUC winter 5-day (AUCW5D)). Posterior heritability estimates were moderate to high and were estimated to be 0.68 and 0.21 for AUCS5D and AUCW5D, respectively. Moderately positive correlations between direct genomic values for AUCS5D and AUCW5D (0.40) were found, although a small percentage of the top 5% 1-Mb windows were in common. Different sets of genes were associated with BT during winter and summer, thus simultaneous selection for animals tolerant to both heat and cold appears possible.

Beef cattle body temperature during climatic stress: a genome-wide association study

NASA Astrophysics Data System (ADS)

Howard, Jeremy T.; Kachman, Stephen D.; Snelling, Warren M.; Pollak, E. John; Ciobanu, Daniel C.; Kuehn, Larry A.; Spangler, Matthew L.

2014-09-01

Cattle are reared in diverse environments and collecting phenotypic body temperature (BT) measurements to characterize BT variation across diverse environments is difficult and expensive. To better understand the genetic basis of BT regulation, a genome-wide association study was conducted utilizing crossbred steers and heifers totaling 239 animals of unknown pedigree and breed fraction. During predicted extreme heat and cold stress events, hourly tympanic and vaginal BT devices were placed in steers and heifers, respectively. Individuals were genotyped with the BovineSNP50K_v2 assay and data analyzed using Bayesian models for area under the curve (AUC), a measure of BT over time, using hourly BT observations summed across 5-days (AUC summer 5-day (AUCS5D) and AUC winter 5-day (AUCW5D)). Posterior heritability estimates were moderate to high and were estimated to be 0.68 and 0.21 for AUCS5D and AUCW5D, respectively. Moderately positive correlations between direct genomic values for AUCS5D and AUCW5D (0.40) were found, although a small percentage of the top 5 % 1-Mb windows were in common. Different sets of genes were associated with BT during winter and summer, thus simultaneous selection for animals tolerant to both heat and cold appears possible.

Defining Winter and Identifying Synoptic Air Mass Change in the Northeast and Northern Plains U.S. since 1950

NASA Astrophysics Data System (ADS)

Chapman, C. J.; Pennington, D.; Beitscher, M. R.; Godek, M. L.

2017-12-01

Understanding and forecasting the characteristics of winter weather change in the northern U.S. is vital to regional economy, agriculture, tourism and resident life. This is especially true in the Northeast and Northern Plains where substantial changes to the winter season have already been documented in the atmospheric science and biological literature. As there is no single established definition of `winter', this research attempts to identify the winter season in both regions utilizing a synoptic climatological approach with air mass frequencies. The Spatial Synoptic Classification is used to determine the daily air mass/ weather type conditions since 1950 at 40 locations across the two regions. Annual frequencies are first computed as a baseline reference. Then winter air mass frequencies and departures from normal are calculated to define the season along with the statistical significance. Once the synoptic winter is established, long-term regional changes to the season and significance are explored. As evident global changes have occurred after 1975, an Early period of years prior to 1975 and a Late set for all years following this date are compared. Early and Late record synoptic changes are then examined to assess any thermal and moisture condition changes of the regional winter air masses over time. Cold to moderately dry air masses dominate annually in both regions. Northeast winters are also characterized by cold to moderate dry air masses, with coastal locations experiencing more Moist Polar types. The Northern Plains winters are dominated by cold, dry air masses in the east and cold to moderate dry air masses in the west. Prior to 1975, Northeast winters are defined by an increase in cooler and wetter air masses. Dry Tropical air masses only occur in this region after 1975. Northern Plains winters are also characterized by more cold, dry air masses prior to 1975. More Dry Moderate and Moist Moderate air masses have occurred since 1975. These results demonstrate that Northeast winters have air mass conditions that have become warmer and drier in recent decades. Additionally, Northern Plains winters have air mass setups that have become warmer and more moist since the mid 1970s.

Geo-spatial analysis of temporal trends of temperature and its extremes over India using daily gridded (1°×1°) temperature data of 1969-2005

NASA Astrophysics Data System (ADS)

Chakraborty, Abhishek; Seshasai, M. V. R.; Rao, S. V. C. Kameswara; Dadhwal, V. K.

2017-10-01

Daily gridded (1°×1°) temperature data (1969-2005) were used to detect spatial patterns of temporal trends of maximum and minimum temperature (monthly and seasonal), growing degree days (GDDs) over the crop-growing season ( kharif, rabi, and zaid) and annual frequencies of temperature extremes over India. The direction and magnitude of trends, at each grid level, were estimated using the Mann-Kendall statistics ( α = 0.05) and further assessed at the homogeneous temperature regions using a field significance test ( α=0.05). General warming trends were observed over India with considerable variations in direction and magnitude over space and time. The spatial extent and the magnitude of the increasing trends of minimum temperature (0.02-0.04 °C year-1) were found to be higher than that of maximum temperature (0.01-0.02 °C year-1) during winter and pre-monsoon seasons. Significant negative trends of minimum temperature were found over eastern India during the monsoon months. Such trends were also observed for the maximum temperature over northern and eastern parts, particularly in the winter month of January. The general warming patterns also changed the thermal environment of the crop-growing season causing significant increase in GDDs during kharif and rabi seasons across India. The warming climate has also caused significant increase in occurrences of hot extremes such as hot days and hot nights, and significant decrease in cold extremes such as cold days and cold nights.

Is Snow a sufficient Source of Water for Horses kept Outdoors in Winter? A Case Report

PubMed Central

Mejdell, CM; Simensen, E; Bøe, KE

2005-01-01

Due to extreme weather conditions, a flock of outwintered Icelandic horses had to manage for several days on snow as the source of free water. They were fed grass silage ad lib, and any change in feed consumption was not observed. After nine days, blood samples were taken and analysed for plasma osmolality, they were subjected to a simple clinical examination, and offered drinking water. Osmolality levels were within normal limits and mean value did not differ significantly from samples which previously were taken of the same individuals. The general condition of the horses was normal, with no signs of clinical dehydration or disease. The horses showed very little interest for the offered drinking water. This suggests that in cold winter weather, horses being fed grass silage and adjusted to eat snow, can manage for several days with snow substituting liquid water without their physiology and welfare being challenged. PMID:16108209

Thermal conditions in the bathroom in winter and summer, and physiological responses of the elderly during bathing.

PubMed

Kanda, K; Tsuchiya, J; Seto, M; Ohnaka, T; Tochihara, Y

1995-06-01

Thermal conditions in the bathroom and physiological responses were examined during winter and summer. The subjects were 22 male and 20 female elderly people, between 65 and 88 years old living in 25 houses in Gunma Prefecture, Japan. Heart rate, blood pressure, skin temperature and thermal sensation were measured during bathing. Changes in thermal sensation due to bathing were assessed in the living room and dressing room on a 9-point scale. Then they were asked about the purposes of bathing and the facilities of bathroom and dressing room. The results are summarized as follows: 1. The purpose of bathing in winter was to warm up for more than 80% of the subjects. In summer, all subjects felt refreshed by bathing. Eighty-five percent of the subjects took a bath every other day in both seasons. 2. Fifty-two percent of the bathrooms had no ventilating fans and 32% had no exclusive dressing rooms. 3. The average room temperature in the dressing rooms was 13-14 degrees C in winter. Thermal sensation was 'cool', 'slightly cold' or 'cold' for more than two-thirds of the subjects when they were partially nude, and there were no heaters in most dressing rooms. 4. The heart rate increased steadily, and reached a maximum value in a partially dressed condition in both seasons. 5. In winter, a marked increase of systolic blood pressure was observed in the partially nude condition. There was a significant difference between the before bathing condition and partially nude condition in winter.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis on energy-saving path of rural buildings in hot summer and cold winter zone

NASA Astrophysics Data System (ADS)

Huang, Mingqiang; Li, Jinheng

2018-02-01

Since the reform and opening policy, the construction of rural area in China has become more and more important. The idea of establishing green villages needs to be accepted and recognized by the public. The hot summer and cold winter zone combines two contradictory weather conditions that is cold winter and hot summer. So the living conditions are limited. In response to this climate, residents extensively use electric heaters or air conditioning to adjust the indoor temperature, resulting in energy waste and environmental pollution. In order to improve the living conditions of residents, rural area energy conservation has been put on the agenda. Based on the present situation and energy consumption analysis of the rural buildings in the hot summer and cold winter zone, this article puts forward several energy saving paths from government, construction technology and so on

Atmospheric Blocking and Atlantic Multi-Decadal Ocean Variability

NASA Technical Reports Server (NTRS)

Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

2011-01-01

Atmospheric blocking over the northern North Atlantic involves isolation of large regions of air from the westerly circulation for 5-14 days or more. From a recent 20th century atmospheric reanalysis (1,2) winters with more frequent blocking persist over several decades and correspond to a warm North Atlantic Ocean, in-phase with Atlantic multi-decadal ocean variability (AMV). Ocean circulation is forced by wind-stress curl and related air/sea heat exchange, and we find that their space-time structure is associated with dominant blocking patterns: weaker ocean gyres and weaker heat exchange contribute to the warm phase of AMV. Increased blocking activity extending from Greenland to British Isles is evident when winter blocking days of the cold years (1900-1929) are subtracted from those of the warm years (1939-1968).

Winter in Antarctica: dark, cold, windy, and .... wet?? Measurements and modeling of extensive wintertime surface melt

NASA Astrophysics Data System (ADS)

Kuipers Munneke, P.; Luckman, A. J.; Bevan, S. L.; Gilbert, E.; Smeets, P.; van den Broeke, M. R.; Wang, W.; Zender, C. S.; Ashmore, D. W.; Hubbard, B. P.; Orr, A.; King, J.

2017-12-01

We know that increased surface melt, driven by atmospheric warming, contributed to the collapse of ice shelves as observed in the Antarctic Peninsula. This has induced grounded-ice acceleration and increased ice discharge. You may associate this surface melt with the austral summer season, with plenty of solar radiation driving the melt. In contrast, winter in Antarctica evokes images of darkness, snow, and cold. However, we will make you rethink this picture by presenting observations of frequent snow surface melt in winter, from a weather station located in a previously unsurveyed area of the Larsen C Ice Shelf. Peak intensities of this wintertime melt even exceed summertime values, and thermal satellite images show that large ponds of meltwater are formed at the surface in the pitch-dark Antarctic winter. Obviously, we wanted to find out what could drive these strong melt events if it's not the sun. It turns out that these multi-day melt events occur when warm and dry föhn winds descend from the Antarctic Peninsula mountains. Simulations with a high-resolution weather model confirm that these winds generate turbulent fluxes of sensible heat, leading to melt fluxes in excess of 200 W m-2. In 2015 and 2016, about 23% of the annual melt was produced in winter. We use satellite radar to show that winter melt occurs on many more places in the Antarctic Peninsula. It happens every year, although in some years the melting is much more widespread than in others. We think that wintertime melt matters as its refreezing warms the snow and increases snow density. In this way, winter melt preconditions the ice shelf for more extensive surface drainage, potentially leading to meltwater-driven instability.

Exploring Winter Community Participation Among Wheelchair Users: An Online Focus Group

PubMed Central

Ripat, Jacquie; Colatruglio, Angela

2016-01-01

ABSTRACT The aim of this qualitative study was to gain an understanding of what people who use wheeled mobility devices (WMDs; e.g., manual and power wheelchairs, and scooters) identify as environmental barriers to community participation in cold weather climates, and to explore recommendations to overcome environmental barriers to community participation. Researchers conducted an online asynchronous focus group that spanned seven days, with eight individuals who use WMDs. Each day, participants were asked to respond to a moderator-provided question, and to engage with one another around the topic area. The researchers analyzed the verbatim data using an inductive content-analysis approach. Four categories emerged from the data: (1) winter barriers to community participation; (2) life resumes in spring and summer; (3) change requires awareness, education, and advocacy; and (4) winter participation is a right. Participants confirmed that it is a collective responsibility to ensure that WMD users are able to participate in the community throughout the seasons. PMID:26295488

Review of the circulation in the Beibu Gulf, South China Sea

NASA Astrophysics Data System (ADS)

Gao, Jingsong; Wu, Guidan; Ya, Hanzheng

2017-04-01

Although Beibu Gulf holds a significant geographical location and is rich in fishery resources, it has attracted only limited attention from researchers in recent decades. This study summarizes the conclusions based on the observations and model results regarding the circulation and cold water mass in the Beibu Gulf to provide a reference for further research. Affected by wind and density gradient, the spring circulation may be gulf-scale cyclonic and nested with an enclosed cyclonic gyre in the northern gulf and unclosed cyclonic gyre in the southern gulf. Meanwhile, the mechanisms of summer circulation remain controversial. Along with the results of a new numerical model, historical observations suggest that summer circulation is cyclonic and anticyclonic in the northern and southern gulfs, respectively. The northern and southern gulfs are mainly influenced by wind stress curl and South China Sea current, respectively. Similarly, although different views regarding the structure of winter circulation have been presented, a large amount of evidence supports the existence of two cyclonic gyres in the northern and southern gulfs. In addition, a southwestward current off the northwestern coast of Hainan Island is present. The circulation structure in the fall is similar to that in winter. However, the cyclonic gyre in the southern Gulf has a greater tendency to intrude northwards into the Beibu Gulf in fall than in winter, and the currents off the coast of Vietnam and the northwestern coast of Hainan Island are weaker in fall than those in winter. Most studies indicate that winter boreal circulation is driven by the monsoon wind. The most recent observations and model results suggest that the current in the Qiongzhou Strait (QS) is eastward on certain days in the boreal summer and is affected by the difference between the sea levels of the two ends of the QS and tidal rectification. Correspondingly, the volume transport is approximately -0.1 Sv (minus sign represents westward) in spring and from -0.1 to -0.4 Sv in boreal winter. By contrast, the volume transport in summer remains controversial. The cold water mass in the Beibu Gulf is generated locally in spring, matures in summer, and disappears in fall. Heat flux and wind dominate the formation of the cold water mass, and tidal mixing and topographic effects influence the variations in the cold water mass.

Effects of extreme temperatures on cardiovascular emergency hospitalizations in a Mediterranean region: a self-controlled case series study.

PubMed

Ponjoan, Anna; Blanch, Jordi; Alves-Cabratosa, Lia; Martí-Lluch, Ruth; Comas-Cufí, Marc; Parramon, Dídac; Del Mar Garcia-Gil, María; Ramos, Rafel; Petersen, Irene

2017-04-04

Cold spells and heatwaves increase mortality. However little is known about the effect of heatwaves or cold spells on cardiovascular morbidity. This study aims to assess the effect of cold spells and heatwaves on cardiovascular diseases in a Mediterranean region (Catalonia, Southern Europe). We conducted a population-based retrospective study. Data were obtained from the System for the Development of Research in Primary Care and from the Catalan Meteorological Service. The outcome was first emergency hospitalizations due to coronary heart disease, stroke, or heart failure. Exposures were: cold spells; cold spells and 3 or 7 subsequent days; and heatwaves. Incidence rate ratios (IRR) and 95% confidence intervals were calculated using the self-controlled case series method. We accounted for age, time trends, and air pollutants; results were shown by age groups, gender or cardiovascular event type. There were 22,611 cardiovascular hospitalizations in winter and 17,017 in summer between 2006 and 2013. The overall incidence of cardiovascular hospitalizations significantly increased during cold spells (IRR = 1.120; CI 95%: 1.10-1.30) and the effect was even stronger in the 7 days subsequent to the cold spell (IRR = 1.29; CI 95%: 1.22-1.36). Conversely, cardiovascular hospitalizations did not increase during heatwaves, neither in the overall nor in the stratified analysis. Cold spells but not heatwaves, increased the incidence of emergency cardiovascular hospitalizations in Catalonia. The effect of cold spells was greater when including the 7 subsequent days. Such knowledge might be useful to develop strategies to reduce the impact of extreme temperature episodes on human health.

The effect of extreme cold temperatures on the risk of death in the two major Portuguese cities

NASA Astrophysics Data System (ADS)

Antunes, Liliana; Silva, Susana Pereira; Marques, Jorge; Nunes, Baltazar; Antunes, Sílvia

2017-01-01

It is well known that meteorological conditions influence the comfort and human health. Southern European countries, including Portugal, show the highest mortality rates during winter, but the effects of extreme cold temperatures in Portugal have never been estimated. The objective of this study was the estimation of the effect of extreme cold temperatures on the risk of death in Lisbon and Oporto, aiming the production of scientific evidence for the development of a real-time health warning system. Poisson regression models combined with distributed lag non-linear models were applied to assess the exposure-response relation and lag patterns of the association between minimum temperature and all-causes mortality and between minimum temperature and circulatory and respiratory system diseases mortality from 1992 to 2012, stratified by age, for the period from November to March. The analysis was adjusted for over dispersion and population size, for the confounding effect of influenza epidemics and controlled for long-term trend, seasonality and day of the week. Results showed that the effect of cold temperatures in mortality was not immediate, presenting a 1-2-day delay, reaching maximum increased risk of death after 6-7 days and lasting up to 20-28 days. The overall effect was generally higher and more persistent in Lisbon than in Oporto, particularly for circulatory and respiratory mortality and for the elderly. Exposure to cold temperatures is an important public health problem for a relevant part of the Portuguese population, in particular in Lisbon.

Winter chilling speeds spring development of temperate butterflies.

PubMed

Stålhandske, Sandra; Gotthard, Karl; Leimar, Olof

2017-07-01

Understanding and predicting phenology has become more important with ongoing climate change and has brought about great research efforts in the recent decades. The majority of studies examining spring phenology of insects have focussed on the effects of spring temperatures alone. Here we use citizen-collected observation data to show that winter cold duration, in addition to spring temperature, can affect the spring emergence of butterflies. Using spatial mixed models, we disentangle the effects of climate variables and reveal impacts of both spring and winter conditions for five butterfly species that overwinter as pupae across the UK, with data from 1976 to 2013 and one butterfly species in Sweden, with data from 2001 to 2013. Warmer springs lead to earlier emergence in all species and milder winters lead to statistically significant delays in three of the five investigated species. We also find that the delaying effect of winter warmth has become more pronounced in the last decade, during which time winter durations have become shorter. For one of the studied species, Anthocharis cardamines (orange tip butterfly), we also make use of parameters determined from previous experiments on pupal development to model the spring phenology. Using daily temperatures in the UK and Sweden, we show that recent variation in spring temperature corresponds to 10-15 day changes in emergence time over UK and Sweden, whereas variation in winter duration corresponds to 20 days variation in the south of the UK versus only 3 days in the south of Sweden. In summary, we show that short winters delay phenology. The effect is most prominent in areas with particularly mild winters, emphasising the importance of winter for the response of ectothermic animals to climate change. With climate change, these effects may become even stronger and apply also at higher latitudes. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Predictability and prediction of the total number of winter extremely cold days over China

NASA Astrophysics Data System (ADS)

Luo, Xiao; Wang, Bin

2018-03-01

The current dynamical climate models have limited skills in predicting winter temperature in China. The present study uses physics-based empirical models (PEMs) to explore the sources and limits of the seasonal predictability in the total number of extremely cold days (NECD) over China. A combined cluster-rotated EOF analysis reveals two sub-regions of homogeneous variability among hundreds of stations, namely the Northeast China (NE) and Main China (MC). This reduces the large-number of predictands to only two indices, the NCED-NE and NCED-MC, which facilitates detection of the common sources of predictability for all stations. The circulation anomalies associated with the NECD-NE exhibit a zonally symmetric Arctic Oscillation-like pattern, whereas those associated with the NECD-MC feature a North-South dipolar pattern over Asia. The predictability of the NECD originates from SST and snow cover anomalies in the preceding September and October. However, the two regions have different SST predictors: The NE predictor is in the western Eurasian Arctic while the MC predictor is over the tropical-North Pacific. The October snow cover predictors also differ: The NE predictor primarily resides in the central Eurasia while the MC predictor is over the western and eastern Eurasia. The PEM prediction results suggest that about 60% (55%) of the total variance of winter NECD over the NE (Main) China are likely predictable 1 month in advance. The NECD at each station can also be predicted by using the four predictors that were detected for the two indices. The cross-validated temporal correlation skills exceed 0.70 at most stations. The physical mechanisms by which the autumn Arctic sea ice, snow cover, and tropical-North Pacific SST anomalies affect winter NECD over the NE and Main China are discussed.

Seasonality intensification and long-term winter cooling as a part of the Late Pliocene climate development

NASA Astrophysics Data System (ADS)

Klotz, Stefan; Fauquette, Séverine; Combourieu-Nebout, Nathalie; Uhl, Dieter; Suc, Jean-Pierre; Mosbrugger, Volker

2006-01-01

A mutual climatic range method is applied to the Mediterranean marine pollen record of Semaforo (Vrica section, Calabria, Italy) covering the period from ∼2.46 Ma to ∼2.11 Ma. The method yields detailed information on summer, annual and winter temperatures and on precipitation during the nine obliquity and precession-controlled 'glacial' periods (marine isotope stages 96 to 80) and eight 'interglacial' periods (marine isotope stages 95 to 81) characterising this time interval. The reconstruction reveals higher temperatures of at least 2.8 °C in mean annual and 2.2 °C in winter temperatures, and 500 mm in precipitation during the 'interglacials' as compared to the present-day climate in the study area. During the 'glacials', temperatures are generally lower as compared to the present-day climate in the region, but precipitation is equivalent. Along the consecutive 'interglacials', a trend toward a reduction in annual and winter temperatures by more than 2.3 °C, and toward a higher seasonality is observed. Along the consecutive 'glacials', a trend toward a strong reduction in all temperature parameters of at least 1.6 °C is reconstructed. Climatic amplitudes of 'interglacial-glacial' transitions increase from the older to the younger cycles for summer and annual temperatures. The cross-spectral analyses suggest obliquity related warm/humid-cold/dry 'interglacial-glacial' cycles which are superimposed by precession related warm/dry- cold/humid cycles. A time displacement in the development of temperatures and precipitation is indicated for the obliquity band by temperatures generally leading precipitation change at ∼4 kyr, and on the precession band of ∼9.6 kyr in maximum.

Record low total ozone during northern winters of 1992 and 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bojkov, R.D.

1993-07-09

The authors look at recorded ozone data over the northern hemisphere during the winters of 1992 and 1993. They use data from the World Meteorological Organization data base. During both of these winter, there have been marked decreases in the column ozone levels over North America, Europe, and Siberia, in the latitude belt from 45[degrees]N to 65[degrees]N. During these winters there have been ten times as many days with ozone levels deviated more than 2[sigma] below the 35 year average. They seek explanations for these observations by looking at meterological information. Evidences indicate that there was transport of ozone deficientmore » air masses during these winters. In addition cold air masses with excess ClO show evidence of having transported into the more southern latitudes. The authors conclude there is evidence for both displacement of large air masses, and increased chemical destruction potential, to have contributed to these observed decreases.« less

Seasonal and diel effects on acoustic fish biomass estimates: application to a shallow reservoir with untargeted common carp (Cyprinus carpio)

USGS Publications Warehouse

Djemali, Imed; Yule, Daniel; Guillard, Jean

2016-01-01

The aim of the present study was to understand how seasonal fish distributions affect acoustically derived fish biomass estimates in a shallow reservoir in a semi-arid country (Tunisia). To that end, sampling events were performed during four seasons (spring (June), summer (September), autumn (December) and winter (March)) that included day and night surveys. A Simrad EK60 echosounder, equipped with two 120-kHz split-beam transducers for simultaneous horizontal and vertical beaming, was used to sample the entire water column. Surveys during spring and summer and daytime hours of winter were deemed unusable owing to high methane flux from the sediment, and during the day survey of autumn, fish were close to the reservoir bottom leading to low detectability. It follows that acoustic surveys should be conducted only at night during the cold season (December–March) for shallow reservoirs having carp Cyprinus carpio (L.) as the dominant species. Further, night-time biomass estimates during the cold season declined significantly (P < 0.001) from autumn to winter. Based on our autumn night-time survey, overall fish biomass in the Bir-Mcherga Reservoir was high (mean (± s.d.) 185 ± 98 tonnes (Mg)), but annual fishery exploitation is low (19.3–24.1 Mg) because the fish biomass is likely dominated by invasive carp not targeted by fishers. The results suggest that controlling carp would help improve the fishery.

Defining winter trophic habitat of juvenile Gulf Sturgeon in the Suwannee and Apalachicola rivermouth estuaries, acoustic telemetry investigations

USGS Publications Warehouse

Sulak, K.J.; Randall, M.T.; Edwards, R.E.; Summers, T.M.; Luke, K.E.; Smith, W.T.; Norem, A.D.; Harden, William M.; Lukens, R.H.; Parauka, F.; Bolden, S.; Lehnert, R.

2009-01-01

Three automated listening post-telemetry studies were undertaken in the Suwannee and Apalachicola estuaries to gain knowledge of habitats use by juvenile Gulf Sturgeons (Acipenser oxyrinchus desotoi) on winter feeding grounds. A simple and reliable method for external attachment of small acoustic tags to the dorsal fin base was developed using shrink-tubing. Suspending receivers on masts below anchored buoys improved reception and facilitated downloading; a detection range of 500–2500 m was realized. In the Apalachicola estuary, juvenile GS stayed in shallow water (< 2 m) within the estuarine transition zone all winter in the vicinity of the Apalachicola River mouth. Juvenile GS high-use areas did not coincide with high density benthic macrofauna areas from the most recent (1999) benthos survey. In the Suwannee estuary, juveniles ranged widely and individually throughout oligohaline to mesohaline subareas of the estuary, preferentially using mesohaline subareas seaward of Suwannee Reef (52% of acoustic detections). The river mouth subarea was important only in early and late winter, during the times of adult Gulf Sturgeon migrations (41% of detections). Preferred winter feeding subareas coincided spatially with known areas of dense macrofaunal benthos concentrations. Following a dramatic drop in air and water temperatures, juvenile GS left the river mouth and estuary, subsequently being detected 8 km offshore in polyhaline open Gulf of Mexico waters, before returning to the estuary. Cold-event offshore excursions demonstrate that they can tolerate full-salinity polyhaline waters in the open Gulf of Mexico, for at least several days at a time. For juvenile sturgeons, the stress and metabolic cost of enduring high salinity (Jarvis et al., 2001; McKenzie et al., 2001; Singer and Ballantyne, 2002) for short periods in deep offshore waters seems adaptively advantageous relative to the risk of cold-event mortality in shallow inshore waters of lower salinity. Thus, while juveniles can tolerate high salinities for days to weeks to escape cold events, they appear to make only infrequent use of open polyhaline waters. Throughout the winter foraging period, juvenile GS stayed primarily within the core area of Suwannee River mouth influence, extending about 12 km north and south of the river mouth, and somewhat seaward of Suwannee Reef (< 5 km offshore). None were detected departing the core area past either of the northern or southern acoustic gates, located 66 and 52 km distant from the river mouth, respectively.

Contrasting cDNA-AFLP profiles between crown and leaf tissues of cold-acclimated wheat plants indicate differing regulatory circuitries for low temperature tolerance.

PubMed

Ganeshan, Seedhabadee; Sharma, Pallavi; Young, Lester; Kumar, Ashwani; Fowler, D Brian; Chibbar, Ravindra N

2011-03-01

Low-temperature (LT) tolerance in winter wheat (Triticum aestivum L.) is an economically important but complex trait. Four selected wheat genotypes, a winter hardy cultivar, Norstar, a tender spring cultivar, Manitou and two near-isogenic lines with Vrn-A1 (spring Norstar) and vrn-A1 (winter Manitou) alleles of Manitou and Norstar were cold-acclimated at 6°C and crown and leaf tissues were collected at 0, 2, 14, 21, 35, 42, 56 and 70 days of cold acclimation. cDNA-AFLP profiling was used to determine temporal expression profiles of transcripts during cold-acclimation in crown and leaf tissues, separately to determine if LT regulatory circuitries in crown and leaf tissues could be delineated using this approach. Screening 64 primer combinations identified 4,074 and 2,757 differentially expressed transcript-derived fragments (TDFs) out of which 38 and 16% were up-regulated as compared to 3 and 6% that were down-regulated in crown and leaf tissues, respectively. DNA sequencing of TDFs revealed sequences common to both tissues including genes coding for DEAD-box RNA helicase, choline-phosphate cytidylyltransferase and delta-1-pyrroline carboxylate synthetase. TDF specific to crown tissues included genes coding for phospahtidylinositol kinase, auxin response factor protein and brassinosteroid insensitive 1-associated receptor kinase. In leaf, genes such as methylene tetrahydrofolate reductase, NADH-cytochrome b5 reductase and malate dehydrogenase were identified. However, 30 and 14% of the DNA sequences from the crown and leaf tissues, respectively, were hypothetical or unknown proteins. Cluster analysis of up-, down-regulated and unique TDFs, DNA sequence and real-time PCR validation, infer that mechanisms operating in crown and leaf tissue in response to LT are differently regulated and warrant further studies.

The role of horizontal thermal advection in regulating wintertime mean and extreme temperatures over the central United States during the past and future

NASA Astrophysics Data System (ADS)

Wang, F.; Vavrus, S. J.

2017-12-01

Horizontal temperature advection plays an especially prominent role in affecting winter climate over continental interiors, where both climatological conditions and extreme weather are strongly regulated by transport of remote air masses. Central North America is one such region, and it experienced a major cold-air outbreak (CAO) a few years ago that some have related to amplified Arctic warming. Despite the known importance of dynamics in shaping the winter climate of this sector and the potential for climate change to modify heat transport, limited attention has been paid to the regional impact of thermal advection. Here, we use a reanalysis product and output from the Community Earth System Model's Large Ensemble to quantify the roles of zonal and meridional temperature advection over the central U. S. during winter, both in the late 20th and 21st centuries. We frame our findings as a "tug of war" between opposing influences of the two advection components and between these dynamical forcings vs. thermodynamic changes under greenhouse warming. For example, Arctic amplification leads to much warmer polar air masses, causing a moderation of cold-air advection into the central U. S., yet the model also simulates a wavier mean circulation and stronger northerly flow during CAOs, favoring lower regional temperatures. We also compare the predominant warming effect of zonal advection and overall cooling effect of meridional temperature advection as an additional tug of war. During both historical and future periods, zonal temperature advection is stronger than meridional advection over the Central U. S. The model simulates a future weakening of both zonal and meridional temperature advection, such that westerly flow provides less warming and northerly flow less cooling. On the most extreme warm days in the past and future, both zonal and meridional temperature advection have positive (warming) contributions. On the most extreme cold days, meridional cold air advection is more important than zonal warm air advection. CAOs in the future feature stronger northerly flow but less extreme temperatures (even relative to the warmer climate), exemplifying the complex competition between thermodynamic and dynamic influences.

Socioenvironmental factors associated with heat and cold-related mortality in Vadu HDSS, western India: a population-based case-crossover study

NASA Astrophysics Data System (ADS)

Ingole, Vijendra; Kovats, Sari; Schumann, Barbara; Hajat, Shakoor; Rocklöv, Joacim; Juvekar, Sanjay; Armstrong, Ben

2017-10-01

Ambient temperatures (heat and cold) are associated with mortality, but limited research is available about groups most vulnerable to these effects in rural populations. We estimated the effects of heat and cold on daily mortality among different sociodemographic groups in the Vadu HDSS area, western India. We studied all deaths in the Vadu HDSS area during 2004-2013. A conditional logistic regression model in a case-crossover design was used. Separate analyses were carried out for summer and winter season. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for total mortality and population subgroups. Temperature above a threshold of 31 °C was associated with total mortality (OR 1.48, CI = 1.05-2.09) per 1 °C increase in daily mean temperature. Odds ratios were higher among females (OR 1.93; CI = 1.07-3.47), those with low education (OR 1.65; CI = 1.00-2.75), those owing larger agricultural land (OR 2.18; CI = 0.99-4.79), and farmers (OR 1.70; CI = 1.02-2.81). In winter, per 1 °C decrease in mean temperature, OR for total mortality was 1.06 (CI = 1.00-1.12) in lag 0-13 days. High risk of cold-related mortality was observed among people occupied in housework (OR = 1.09; CI = 1.00-1.19). Our study suggests that both heat and cold have an impact on mortality particularly heat, but also, to a smaller degree, cold have an impact. The effects may differ partly by sex, education, and occupation. These findings might have important policy implications in preventing heat and cold effects on particularly vulnerable groups of the rural populations in low and middle-income countries with hot semi-arid climate.

Linking the pacific decadal oscillation to seasonal stream discharge patterns in Southeast Alaska

USGS Publications Warehouse

Neal, E.G.; Todd, Walter M.; Coffeen, C.

2002-01-01

This study identified and examined differences in Southeast Alaskan streamflow patterns between the two most recent modes of the Pacific decadal oscillation (PDO). Identifying relationships between the PDO and specific regional phenomena is important for understanding climate variability, interpreting historical hydrological variability, and improving water-resources forecasting. Stream discharge data from six watersheds in Southeast Alaska were divided into cold-PDO (1947-1976) and warm-PDO (1977-1998) subsets. For all watersheds, the average annual streamflows during cold-PDO years were not significantly different from warm-PDO years. Monthly and seasonal discharges, however, did differ significantly between the two subsets, with the warm-PDO winter flows being typically higher than the cold-PDO winter flows and the warm-PDO summer flows being typically lower than the cold-PDO flows. These results were consistent with and driven by observed temperature and snowfall patterns for the region. During warm-PDO winters, precipitation fell as rain and ran-off immediately, causing higher than normal winter streamflow. During cold-PDO winters, precipitation was stored as snow and ran off during the summer snowmelt, creating greater summer streamflows. The Mendenhall River was unique in that it experienced higher flows for all seasons during the warm-PDO relative to the cold-PDO. The large amount of Mendenhall River discharge caused by glacial melt during warm-PDO summers offset any flow reduction caused by lack of snow accumulation during warm-PDO winters. The effect of the PDO on Southeast Alaskan watersheds differs from other regions of the Pacific Coast of North America in that monthly/seasonal discharge patterns changed dramatically with the switch in PDO modes but annual discharge did not. ?? 2002 Elsevier Science B.V. All rights reserved.

Winter wheat response to irrigation, nitrogen fertilization, and cold hazards in the Community Land Model 5

NASA Astrophysics Data System (ADS)

Lu, Y.

2017-12-01

Winter wheat is a staple crop for global food security, and is the dominant vegetation cover for a significant fraction of earth's croplands. As such, it plays an important role in soil carbon balance, and land-atmosphere interactions in these key regions. Accurate simulation of winter wheat growth is not only crucial for future yield prediction under changing climate, but also for understanding the energy and water cycles for winter wheat dominated regions. A winter wheat growth model has been developed in the Community Land Model 4.5 (CLM4.5), but its responses to irrigation and nitrogen fertilization have not been validated. In this study, I will validate winter wheat growth response to irrigation and nitrogen fertilization at five winter wheat field sites (TXLU, KSMA, NESA, NDMA, and ABLE) in North America, which were originally designed to understand winter wheat response to nitrogen fertilization and water treatments (4 nitrogen levels and 3 irrigation regimes). I also plan to further update the linkages between winter wheat yield and cold hazards. The previous cold damage function only indirectly affects yield through reduction on leaf area index (LAI) and hence photosynthesis, such approach could sometimes produce an unwanted higher yield when the reduced LAI saved more nutrient in the grain fill stage.

Variable role of aquatic macroinvertebrates in initial breakdown of seasonal leaf litter inputs to a cold-desert river

USGS Publications Warehouse

Nelson, S.M.; Andersen, D.C.

2007-01-01

We used coarse-mesh and fine-mesh leafpacks to examine the importance of aquatic macroinvertebrates in the breakdown of floodplain tree leaf litter that seasonally entered a sand-bedded reach of the sixth-order Yampa River in semiarid Colorado. Leafpacks were positioned off the easily mobilized channel bed, mimicking litter trapped in debris piles. Organic matter (OM) loss was fastest for leaves collected from the floodplain and placed in the river in spring (k = 0.029/day) and slowest for leaves collected and placed in the river in winter (0.006/day). Macroinvertebrates were most abundant in winter and spring leaves, but seemed important to processing only in spring, when exclusion by fine mesh reduced OM loss by 25% and nitrogen loss by 65% in spring leaves. Macroinvertebrates seemed to have little role in processing of autumn, winter, or summer leaves over the 50-day to 104-day monitoring periods. Desiccation during bouts of low discharge and sediment deposition on leaves limited invertebrate processing in summer and autumn, whereas processing of winter leaves, which supported relatively large numbers of shredders, might have been restricted by ice formation and low water temperatures. These results were consistent with the concept that microbial processing dominates in higher-order rivers, but suggested that macroinvertebrate processing can be locally important in higher-order desert rivers in seasons or years with favorable discharge and water quality conditions.

Randomized controlled trial of probiotics to reduce common cold in schoolchildren.

PubMed

Rerksuppaphol, Sanguansak; Rerksuppaphol, Lakkana

2012-10-01

The common cold is responsible for the largest proportion of school and work absenteeism and causes a huge economic burden. None of the current interventions is greatly effective for prevention. Our aim was to assess the efficacy of a two-strain combination probiotic for prevention of common cold symptoms in healthy schoolchildren. A double-blind randomized controlled trial was performed during the winter season in a public school of central Thailand. Children, aged 8-13 years, were randomized to receive either a two-strain combination probiotic (Lactobacillus acidophilus and Bifidobacterium bifidum) or placebo given twice a day for 3 months. The primary outcome was any symptom of cold during the 3-month study period while vomiting, diarrhea, use of antibiotics, school absence due to any cause, school absence due to cold and duration of all symptoms were secondary outcomes. Of the 40 children in each group, 31 (77%) in the probiotic group, compared to 38 (95%) in the placebo group (P= 0.048), developed at least one symptom of cold. Children in the probiotics group had significantly lower risk of fever, cough, rhinorrhea, school absence and school absence related to common cold compared to children in the placebo group. There was no impact on diarrhea and vomiting. A two-strain probiotic combination given twice a day for 3 months was able to reduce the symptoms of the common cold and school absenteeism in schoolchildren. © 2012 The Authors. Pediatrics International © 2012 Japan Pediatric Society.

Human cold stress of strong local-wind "Hijikawa-arashi" in Japan, based on the UTCI index and thermo-physiological responses

NASA Astrophysics Data System (ADS)

Ohashi, Yukitaka; Katsuta, Takumi; Tani, Haruka; Okabayashi, Taiki; Miyahara, Satoshi; Miyashita, Ryoji

2018-03-01

We investigated the cold stress caused by a strong local wind called "Hijikawa-arashi," through in situ vital measurements and the Universal Thermal Climate Index (UTCI). This wind is a very interesting winter phenomenon, localized in an area within 1 km of the seashore in Ozu City, Ehime Prefecture in Japan. When a strong Hijikawa-arashi (HA) occurred at 14-15 m s-1, the UTCI decreased to - 30 °C along the bridge where commuting residents are the most exposed to strong and cold winds. On the bridge, most participants in our experiment felt "very cold" or "extremely cold." The UTCI of HA can be predicted from a multiple regression equation using wind speed and air temperature. The cold HA wind is also harmful to human thermo-physiological responses. It leads to higher blood pressure and increased heart rate, both of which act as cardiovascular stress triggers. Increases of 6-10 mmHg and 3-6 bpm for every 10 °C reduction in UTCI were seen on all observational days, including HA and non-HA days. In fact, the participants' body skin temperatures decreased by approximately 1.2 to 1.7 °C for every 10 °C reduction in UTCI. Thus, the UTCI variation due to the HA outbreak corresponded well with the cold sensation and thermo-physiological responses in humans. This result suggests that daily UTCI monitoring enables the prediction of thermo-physiological responses to the HA cold stress.

Intra-seasonal Characteristics of Wintertime Extreme Cold Events over South Korea

NASA Astrophysics Data System (ADS)

Park, Taewon; Jeong, Jeehoon; Choi, Jahyun

2017-04-01

The present study reveals the changes in the characteristics of extreme cold events over South Korea for boreal winter (November to March) in terms of the intra-seasonal variability of frequency, duration, and atmospheric circulation pattern. Influences of large-scale variabilities such as the Siberian High activity, the Arctic Oscillation (AO), and the Madden-Julian Oscillation (MJO) on extreme cold events are also investigated. In the early and the late of the winter during November and March, the upper-tropospheric wave-train for a life-cycle of the extreme cold events tends to pass quickly over East Asia. In addition, compared with the other months, the intensity of the Siberian High is weaker and the occurrences of strong negative AO are less frequent. It lead to events with weak amplitude and short duration. On the other hand, the amplified Siberian High and the strong negative AO occur more frequently in the mid of the winter from December to February. The extreme cold events are mainly characterized by a well-organized anticyclonic blocking around the Ural Mountain and the Subarctic. These large-scale circulation makes the extreme cold events for the midwinter last long with strong amplitude. The MJO phases 2-3 which provide a suitable condition for the amplification of extreme cold events occur frequently for November to January when the frequencies are more than twice those for February and March. While the extreme cold events during March have the least frequency, the weakest amplitude, and the shortest duration due to weak impacts of the abovementioned factors, the strong activities of the factors for January force the extreme cold events to be the most frequent, the strongest, and the longest among the boreal winter. Keywords extreme cold event, wave-train, blocking, Siberian High, AO, MJO

Preventing cold-related morbidity and mortality in a changing climate

PubMed Central

Conlon, Kathryn C; Rajkovich, Nicholas B; White-Newsome, Jalonne L; Larsen, Larissa; Neill, Marie S O

2011-01-01

Winter weather patterns are anticipated to become more variable with increasing average global temperatures. Research shows that excess morbidity and mortality occurs during cold weather periods. We critically reviewed evidence relating temperature variability, health outcomes, and adaptation strategies to cold weather. Health outcomes included cardiovascular-, respiratory-, cerebrovascular-, and all-cause morbidity and mortality. Individual and contextual risk factors were assessed to highlight associations between individual- and neighborhood- level characteristics that contribute to a person’s vulnerability to variability in cold weather events. Epidemiologic studies indicate that the populations most vulnerable to variations in cold winter weather are the elderly, rural and, generally, populations living in moderate winter climates. Fortunately, cold-related morbidity and mortality are preventable and strategies exist for protecting populations from these adverse health outcomes. We present a range of adaptation strategies that can be implemented at the individual, building, and neighborhood level to protect vulnerable populations from cold-related morbidity and mortality. The existing research justifies the need for increased outreach to individuals and communities for education on protective adaptations in cold weather. We propose that future climate change adaptation research couple building energy and thermal comfort models with epidemiological data to evaluate and quantify the impacts of adaptation strategies. PMID:21592693

Adaptations to terrestrial overwintering of hatchling northern map turtles, Graptemys geographica.

PubMed

Baker, P J; Costanzo, J P; Iverson, J B; Lee, R E

2003-11-01

We conducted a 3-year field and laboratory study of winter biology in hatchlings of the northern map turtle ( Graptemys geographica). At our study area in northern Indiana, hatchlings routinely overwintered in their natal nests, emerging after the weather warmed in spring. Winter survival was excellent despite the fact that hatchlings were exposed frequently to subfreezing temperatures (to -5.4 degrees C). In the laboratory, cold-acclimated hatchlings exhibited low rates of evaporative water loss (mean=2.0 mg g(-1) day(-1)), which would enable them to conserve body water during winter. Laboratory-reared hatchlings were intolerant of freezing at -2.5 degrees C for 24 h, conditions that are readily survived by freeze-tolerant species of turtles. Winter survival of hatchling G. geographica probably depended on their extensive capacity for supercooling (to -14.8 degrees C) and their well-developed resistance to inoculative freezing, which may occur when hatchlings contact ice and ice-nucleating agents present in nesting soil. Supercooled hatchlings survived a brief exposure to -8 degrees C. Others, held at -6 degrees C for 5 days, maintained ATP concentrations at control levels, although they did accumulate lactate and glucose, probably in response to tissue hypoxia. Therefore, anoxia tolerance, as evidenced by the viability of hatchlings exposed to N(2) gas for 8 days, may promote survival during exposure to subfreezing temperatures.

Wildfires, mountain pine beetle and large-scale climate in Northern North America.

NASA Astrophysics Data System (ADS)

Macias Fauria, M.; Johnson, E. A.

2009-05-01

Research on the interactions between biosphere and atmosphere and ocean/atmosphere dynamics, concretely on the coupling between ecological processes and large-scale climate, is presented in two studies in Northern North America: the occurrence of large lightning wildfires and the forest area affected by mountain pine beetle (Dendroctonus ponderosae, MPB). In both cases, large-scale climatic patterns such as the Pacific Decadal Oscillation (PDO) and the Arctic Oscillation (AO) operate as low and low and high frequency frameworks, respectively, that control the occurrence, duration and spatial correlation over large areas of key local weather variables which affect specific ecological processes. Warm PDO phases tend to produce persistent (more than 10 days long) positive mid-troposphere anomalies (blocking highs) over western Canada and Alaska. Likewise, positive (negative) AO configurations increase the frequency of blocking highs at mid (high) latitudes of the Northern Hemisphere. Under these conditions, lack of precipitation and prevailing warm air meridional flow rapidly dry fuel over large areas and increase fire hazard. The spatiotemporal patterns of occurrence of large lightning wildfire in Canada and Alaska for 1959-1999 were largely explained by the action and possible interaction of AO and PDO, the AO being more influential over Eastern Canada, the PDO over Western Canada and Alaska. Changes in the dynamics of the PDO are linked to the occurrence of cold winter temperatures in British Columbia (BC), Western Canada. Reduced frequency of cold events during warm PDO winters is consistent with a northward-displaced polar jet stream inhibiting the outflow of cold Arctic air over BC. Likewise, the AO influences the occurrence of winter cold spells in the area. PDO, and to a lesser degree AO, were strongly related to MPB synchrony in BC during 1959-2002, operating through the control of the frequency of extreme cold winter temperatures that affect MPB larvae survival. The onset of a warm PDO phase in 1976 1) increased (decreased) the area burnt by wildfire in the Canadian Boreal Forest (BC) by increasing (decreasing) the frequency of blocking highs in the area, and 2) favored MPB outbreaks in BC by reducing the occurrence of extremely low winter temperatures. Likewise, the exceptionally high and persistent AO values of the late 1980s and 1990s increased area burned in Eastern Canada and MPB activity in the southern and northern parts of BC. A possible recent PDO phase shift may largely reverse these trends.

Simulated trends of extreme climate indices for the Carpathian basin using outputs of different regional climate models

NASA Astrophysics Data System (ADS)

Pongracz, R.; Bartholy, J.; Szabo, P.; Pieczka, I.; Torma, C. S.

2009-04-01

Regional climatological effects of global warming may be recognized not only in shifts of mean temperature and precipitation, but in the frequency or intensity changes of different climate extremes. Several climate extreme indices are analyzed and compared for the Carpathian basin (located in Central/Eastern Europe) following the guidelines suggested by the joint WMO-CCl/CLIVAR Working Group on climate change detection. Our statistical trend analysis includes the evaluation of several extreme temperature and precipitation indices, e.g., the numbers of severe cold days, winter days, frost days, cold days, warm days, summer days, hot days, extremely hot days, cold nights, warm nights, the intra-annual extreme temperature range, the heat wave duration, the growing season length, the number of wet days (using several threshold values defining extremes), the maximum number of consecutive dry days, the highest 1-day precipitation amount, the greatest 5-day rainfall total, the annual fraction due to extreme precipitation events, etc. In order to evaluate the future trends (2071-2100) in the Carpathian basin, daily values of meteorological variables are obtained from the outputs of various regional climate model (RCM) experiments accomplished in the frame of the completed EU-project PRUDENCE (Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects). Horizontal resolution of the applied RCMs is 50 km. Both scenarios A2 and B2 are used to compare past and future trends of the extreme climate indices for the Carpathian basin. Furthermore, fine-resolution climate experiments of two additional RCMs adapted and run at the Department of Meteorology, Eotvos Lorand University are used to extend the trend analysis of climate extremes for the Carpathian basin. (1) Model PRECIS (run at 25 km horizontal resolution) was developed at the UK Met Office, Hadley Centre, and it uses the boundary conditions from the HadCM3 GCM. (2) Model RegCM3 (run at 10 km horizontal resolution) was developed by Giorgi et al. and it is available from the ICTP (International Centre for Theoretical Physics). Analysis of the simulated daily temperature datasets suggests that the detected regional warming is expected to continue in the 21st century. Cold temperature extremes are projected to decrease while warm extremes tend to increase significantly. Expected changes of annual precipitation indices are small, but generally consistent with the detected trends of the 20th century. Based on the simulations, extreme precipitation events are expected to become more intense and more frequent in winter, while a general decrease of extreme precipitation indices is expected in summer.

Arctic sea ice loss and recent extreme cold winter in Eurasia

NASA Astrophysics Data System (ADS)

Mori, Masato; Watanabe, Masahiro; Ishii, Masayoshi; Kimoto, Masahide

2014-05-01

Extreme cold winter over the Eurasia has occurred more frequently in recent years. Observational evidence in recent studies shows that the wintertime cold anomalies over the Eurasia are associated with decline of Arctic sea ice in preceding autumn to winter season. However, the tropical and/or mid-latitude sea surface temperature (SST) anomalies have great influence on the mid- and high-latitude atmospheric variability, it is difficult to isolate completely the impacts of sea ice change from observational data. In this study, we examine possible linkage between the Arctic sea ice loss and the extreme cold winter over the Eurasia using a state-of-the-art MIROC4 (T106L56) atmospheric general circulation model (AGCM) to assess the pure atmospheric responses to sea ice reduction. We perform two sets of experiments with different realistic sea ice boundary conditions calculated by composite of observed sea ice concentration; one is reduced sea ice extent case (referred to as LICE run) and another is enhanced case (HICE run). In both experiments, the model is integrated 6-month from September to February with 100-member ensemble under the climatological SST boundary condition. The difference in ensemble mean of each experiment (LICE minus HICE) shows cold anomalies over the Eurasia in winter and its spatial pattern is very similar to corresponding observation, though the magnitude is smaller than observation. This result indicates that a part of observed cold anomaly can be attributed to the Arctic sea ice loss. We would like to introduce more important results and mechanisms in detail in my presentation.

Experimental evidence for beneficial effects of projected climate change on hibernating amphibians.

PubMed

Üveges, Bálint; Mahr, Katharina; Szederkényi, Márk; Bókony, Veronika; Hoi, Herbert; Hettyey, Attila

2016-05-27

Amphibians are the most threatened vertebrates today, experiencing worldwide declines. In recent years considerable effort was invested in exposing the causes of these declines. Climate change has been identified as such a cause; however, the expectable effects of predicted milder, shorter winters on hibernation success of temperate-zone Amphibians have remained controversial, mainly due to a lack of controlled experimental studies. Here we present a laboratory experiment, testing the effects of simulated climate change on hibernating juvenile common toads (Bufo bufo). We simulated hibernation conditions by exposing toadlets to current (1.5 °C) or elevated (4.5 °C) hibernation temperatures in combination with current (91 days) or shortened (61 days) hibernation length. We found that a shorter winter and milder hibernation temperature increased survival of toads during hibernation. Furthermore, the increase in temperature and shortening of the cold period had a synergistic positive effect on body mass change during hibernation. Consequently, while climate change may pose severe challenges for amphibians of the temperate zone during their activity period, the negative effects may be dampened by shorter and milder winters experienced during hibernation.

Public health vulnerability to wintertime weather: time-series regression and episode analyses of national mortality and morbidity databases to inform the Cold Weather Plan for England.

PubMed

Hajat, S; Chalabi, Z; Wilkinson, P; Erens, B; Jones, L; Mays, N

2016-08-01

To inform development of Public Health England's Cold Weather Plan (CWP) by characterizing pre-existing relationships between wintertime weather and mortality and morbidity outcomes, and identification of groups most at risk. Time-series regression analysis and episode analysis of daily mortality, emergency hospital admissions, and accident and emergency visits for each region of England. Seasonally-adjusted Poisson regression models estimating the percent change in daily health events per 1 °C fall in temperature or during individual episodes of extreme weather. Adverse cold effects were observed in all regions, with the North East, North West and London having the greatest risk of cold-related mortality. Nationally, there was a 3.44% (95% CI: 3.01, 3.87) increase in all-cause deaths and 0.78% (95% CI: 0.53, 1.04) increase in all-cause emergency admissions for every 1 °C drop in temperature below identified thresholds. The very elderly and people with COPD were most at risk from low temperatures. A&E visits for fractures were elevated during heavy snowfall periods, with adults (16-64 years) being the most sensitive age-group. Since even moderately cold days are associated with adverse health effects, by far the greatest health burdens of cold weather fell outside of the alert periods currently used in the CWP. Our findings indicate that levels 0 ('year round planning') and 1 ('winter preparedness and action') are crucial components of the CWP in comparison to the alerts. Those most vulnerable during winter may vary depending on the type of weather conditions being experienced. Recommendations are made for the CWP. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Relationship between seasonal cold acclimatization and mtDNA haplogroup in Japanese

PubMed Central

2012-01-01

Background The purpose of this study was to elucidate the interaction between mtDNA haplogroup and seasonal variation that contributes to cold adaptation. Methods There were 15 subjects (seven haplotype D subjects and eight haplotype non-D subjects). In summer and winter, the subjects were placed in an environment where the ambient temperature dropped from 27 °C to 10 °C in 30 minutes. After that, they were exposed to cold for 60 minutes. Results In summer, the decrease in rectal temperature and increase in oxygen consumption was smaller and cold tolerance was higher in the haplotype non-D group than in the haplotype D group. In winter, no significant differences were seen in rectal temperature or oxygen consumption, but the respiratory exchange ratio decreased in the haplotype D group. Conclusions The results of the present study suggest that haplogroup D subjects are a group that changes energy metabolism more, and there appears to be a relationship between differences in cold adaptability and mtDNA polymorphism within the population. Moreover, group differences in cold adaptability seen in summer may decrease in winter due to supplementation by seasonal cold acclimatization. PMID:22929588

Recent temperature trends in the South Central Andes reconstructed from sedimentary chrysophyte stomatocysts in Laguna Escondida (1742 m a.s.l., 38°28 S, Chile)

NASA Astrophysics Data System (ADS)

De Jong, R.; Schneider, T.; Hernández-Almeida, I.; Grosjean, M.

2016-02-01

In this study we present a quantitative, high resolution reconstruction of past austral winter length in the Chilean Andes at 38°S from AD 1920 to 2009. For Laguna Escondida, a nearly pristine lake situated on the flanks of the Andes at 1740 m above sea level, past variability in the duration of the winter season (Days T4 °C) was reconstructed. Because high elevation meteorological stations are absent in this region, the reconstruction provides novel insights into recent temperature trends in the central-southern Andes. As a cold-season temperature proxy, we used chrysophyte stomatocysts. This novel proxy for cold season temperature was so far applied successfully in the European Alps and Pyrenees but has not yet been tested in the Southern Hemisphere. The reconstruction in this study was based on a newly developed Transfer Function to estimate Days T4 °C (number of consecutive days with surface water temperatures at or below 4 °C) from sedimentary stomatocyst assemblages (R2boot = 0.8, RMSEPboot = 28.7 days (= half the standard deviation)). To develop a high quality TF model, sediment traps and thermistors were placed in thirty remote lakes along an altitude gradient (420-2040 m a.s.l.). Complete materials and data were collected in 24 lakes after one year. Detailed statistical analyses indicate that modern stomatocysts primarily respond to the length of the cold season. The TF model was then applied to the sedimentary stomatocysts from a 210Pb-dated short core of L. Escondida. Comparison to independent reanalysis data showed that reconstructed changes in Days T4°C provides detailed information on winter-spring temperature variability since AD 1920. The reconstruction shows that recent warming (onset in AD 1980) in the southern Chilean Andes was not exceptional in the context of the past century. This is in strong contrast to studies from the Northern Hemisphere. The finding is also in contrast to the cooling temperature trends which were detected using meteorological measurement data in low altitude sites along the Chilean coast. This finding confirms that coastal meteorological station data in this region do not reliably reflect recent temperature trends at high altitudes. Moreover, it implies a southward shift of the northern border of the Westerlies wind belt. This study clearly illustrates the importance of quantitative, high resolution studies from remote sites, in particular at high elevation mountain areas.

Assessing the Climate Sensitivity of Cold Content and Snowmelt in Seasonal Alpine and Subalpine Snowpacks

NASA Astrophysics Data System (ADS)

Jennings, K. S.; Molotch, N. P.

2016-12-01

In cold, high-elevation sites, snowpack cold content acts as a buffer against climate warming by resisting snowmelt during periods of positive energy fluxes. To test the climate sensitivity of cold content and snowmelt, we employed the physical SNOWPACK snow model, forced with a 23-year, hourly, quality-controlled, gap-filled meteorological dataset from the Niwot Ridge Long Term Ecological Research (LTER) site in the Front Range mountains of Colorado. SNOWPACK was run at two points with seasonal snowpacks within the LTER, one in the alpine (3528 m) and one in the subalpine (3022 m). Model output was validated using snow water equivalent (SWE), snowpack temperature, and cold content data from snow pits dug near the met stations and automated SWE data from nearby SNOTEL snow pillows. Cold content accumulates primarily through additions of new snow, while negative energy fluxes—cooling through longwave emission and sublimation—play a lesser role, particularly in the deeper snowpack of the alpine. On average, the snowpack energy balance becomes positive on April 1 in the alpine and March 8 in the subalpine. Peak SWE occurs after these dates and its timing is primarily determined by the amount of precipitation received after peak cold content, with persistent snowfall delaying the main snowmelt pulse. Years with lower cold content, due to reduced precipitation and/or increased air temperature, experience an earlier positive energy balance with more melt events occurring before the date of peak SWE, which has implications for soil moisture, streamflow volume and timing, water uptake by vegetation, and microbial respiration. Synthetic warming experiments show significant cold content reductions and increased late-winter/early-spring melt as positive energy balances occur earlier in the snow season (a forward shift between 5.1 and 21.0 days per °C of warming). These results indicate cold, high-elevation sites, which are critical for water resources in the western United States, may lose their cold content buffering capacity and begin to experience stronger negative trends in SWE with increased climate warming, even as the majority of winter precipitation continues to fall as snow.

Winter severity and phenology of spring emergence from the nest in freshwater turtles.

PubMed

Baker, Patrick Joseph; Iverson, John B; Lee, Richard E; Costanzo, Jon P

2010-07-01

Although many species of freshwater turtles emigrate to water soon after hatching, the offspring of some species overwinter on land and move to aquatic habitats in the following spring. Timing of emigration can affect the hatchlings' fitness, but the factors underlying phenology of nest emergence are incompletely understood. We tested the supposition that cold stress imposed during hibernation can influence the timing of nest emergence in three species of turtles in the central USA. In each year of the 6-year study, Chrysemys picta emerged in late March and early April and, on average, these hatchlings left their nests 2 weeks earlier than those of Graptemys geographica and 4 weeks earlier than those of Trachemys scripta. Emergence of conspecific hatchlings from different nests usually occurred over 3-7 weeks, but in some years lasted several additional weeks. Relatively few nests had siblings that emerged on the same day (i.e., synchronously); complete emergence of the typical sibling group required 1 to 2 weeks. In winter, subzero cold occurred with regularity in the nests of all species, though C. picta experienced the lowest temperatures owing to their shallower nests. However, for no species did emergence date or length of the emergence period correlate with winter minimum temperature and, at the level of the individual nest, neither did emergence synchrony or duration. Despite encountering lower temperatures, hatchlings of C. picta emigrated from their nests before those of sympatric species, suggesting that the fitness benefits of early emergence may lead to the improvement of cold-hardiness adaptations in northern populations of turtles.

Winter severity and phenology of spring emergence from the nest in freshwater turtles

NASA Astrophysics Data System (ADS)

Baker, Patrick Joseph; Iverson, John B.; Lee, Richard E.; Costanzo, Jon P.

2010-07-01

Although many species of freshwater turtles emigrate to water soon after hatching, the offspring of some species overwinter on land and move to aquatic habitats in the following spring. Timing of emigration can affect the hatchlings’ fitness, but the factors underlying phenology of nest emergence are incompletely understood. We tested the supposition that cold stress imposed during hibernation can influence the timing of nest emergence in three species of turtles in the central USA. In each year of the 6-year study, Chrysemys picta emerged in late March and early April and, on average, these hatchlings left their nests 2 weeks earlier than those of Graptemys geographica and 4 weeks earlier than those of Trachemys scripta. Emergence of conspecific hatchlings from different nests usually occurred over 3-7 weeks, but in some years lasted several additional weeks. Relatively few nests had siblings that emerged on the same day (i.e., synchronously); complete emergence of the typical sibling group required 1 to 2 weeks. In winter, subzero cold occurred with regularity in the nests of all species, though C. picta experienced the lowest temperatures owing to their shallower nests. However, for no species did emergence date or length of the emergence period correlate with winter minimum temperature and, at the level of the individual nest, neither did emergence synchrony or duration. Despite encountering lower temperatures, hatchlings of C. picta emigrated from their nests before those of sympatric species, suggesting that the fitness benefits of early emergence may lead to the improvement of cold-hardiness adaptations in northern populations of turtles.

Logistic Regression Analysis of the Response of Winter Wheat to Components of Artificial Freezing Episodes

USDA-ARS?s Scientific Manuscript database

Improvement of cold tolerance of winter wheat (Triticum aestivum L.) through breeding methods has been problematic. A better understanding of how individual wheat cultivars respond to components of the freezing process may provide new information that can be used to develop more cold tolerance culti...

High cold tolerance through four seasons and all free-living stages in an ectoparasite.

PubMed

Härkönen, Laura; Kaitala, Arja; Kaunisto, Sirpa; Repo, Tapani

2012-06-01

Off-host stages of temperate parasites must cope with low temperatures. Cold tolerance is often highest in winter, as a result of diapause and cold acclimation, and low during the active summer stages. In some blood-feeding ectoparasites, offspring provisioning determines cold tolerance through all the non-feeding, off-host stages. Large size increases survival in the cold, but so far seasonal variation in within-female offspring size has not been associated with offspring cold tolerance. The deer ked (Lipoptena cervi) reproduces on cervids from autumn to spring. Newborn pupae drop off the host, facing frosts without any acclimation. We examined cold tolerance through 4 seasons and from birth to adulthood by means of short- and long-term frost exposure. We expected females to produce more tolerant offspring in winter than in spring. Large spring pupae survived prolonged frosts better than did small winter pupae. Thus more tolerant offspring were not produced when the temperature outside the host is at its lowest. Unexpectedly, the freezing points were -20 °C or below all year round. We showed that high cold tolerance is possible without acclimation regardless of life stage, which presumably correlates with other survival characteristics, such as the starvation resistance of free-living ectoparasites.

Comparison of UTCI with Other Thermal Indices in the Assessment of Heat and Cold Effects on Cardiovascular Mortality in the Czech Republic

PubMed Central

Urban, Aleš; Kyselý, Jan

2014-01-01

We compare the recently developed Universal Thermal Climate Index (UTCI) with other thermal indices in analysing heat- and cold-related effects on cardiovascular (CVD) mortality in two different (urban and rural) regions in the Czech Republic during the 16-year period from 1994–2009. Excess mortality is represented by the number of deaths above expected daily values, the latter being adjusted for long-term changes, annual and weekly cycles, and epidemics of influenza/acute respiratory infections. Air temperature, UTCI, Apparent Temperature (AT) and Physiologically Equivalent Temperature (PET) are applied to identify days with heat and cold stress. We found similar heat effects on CVD mortality for air temperature and the examined thermal indices. Responses of CVD mortality to cold effects as characterised by different indices were much more varied. Particularly important is the finding that air temperature provides a weak cold effect in comparison with the thermal indices in both regions, so its application—still widespread in epidemiological studies—may underestimate the magnitude of cold-related mortality. These findings are important when possible climate change effects on heat- and cold-related mortality are estimated. AT and PET appear to be more universal predictors of heat- and cold- related mortality than UTCI when both urban and rural environments are of concern. UTCI tends to select windy rather than freezing days in winter, though these show little effect on mortality in the urban population. By contrast, significant cold-related mortality in the rural region if UTCI is used shows potential for UTCI to become a useful tool in cold exposure assessments. PMID:24413706

Huddling Conserves Energy, Decreases Core Body Temperature, but Increases Activity in Brandt's Voles (Lasiopodomys brandtii)

PubMed Central

Sukhchuluun, Gansukh; Zhang, Xue-Ying; Chi, Qing-Sheng; Wang, De-Hua

2018-01-01

Huddling as social thermoregulatory behavior is commonly used by small mammals to reduce heat loss and energy expenditure in the cold. Our study aimed to determine the effect of huddling behavior on energy conservation, thermogenesis, core body temperature (Tb) regulation and body composition in Brandt's voles (Lasiopodomys brandtii). Adult captive-bred female Brandt's voles (n = 124) (~50 g) in 31 cages with 4 individuals each were exposed to cool (23 ± 1°C) and cold (4 ± 1°C) ambient temperatures (Ta) and were allowed to huddle or were physically separated. The cold huddling (Cold-H) groups significantly reduced food intake by 29% and saved digestible energy 156.99 kJ/day compared with cold separated groups (Cold-S); in cool huddling groups (Cool-H) the reduction in food intake was 26% and digestible energy was saved by 105.19 kJ/day in comparison to the separated groups (Cool-S). Resting metabolic rate (RMR) of huddling groups was 35.7 and 37.2% lower than in separated groups at cold and cool Tas, respectively. Maximum non-shivering thermogenesis (NSTmax) of huddling voles was not affected by Ta, but in Cold-S voles it was significantly increased in comparison to Cool-S. Huddling groups decreased wet thermal conductance by 39% compared with separated groups in the cold, but not in the cool Ta. Unexpectedly, huddling voles significantly decreased Tb by 0.25 – 0.50°C at each Ta. Nevertheless, activity of Cold-H voles was higher than in Cold-S voles. Thus, huddling is energetically highly effective because of reduced metabolic rate, thermogenic capacity and relaxed Tb regulation despite the increase of activity. Therefore, Brandt's voles can remain active and maintain their body condition without increased energetic costs during cold exposure. This study highlights the ecological significance of huddling behavior for maintenance of individual fitness at low costs, and thus survival of population during severe winter in small mammals. PMID:29867585

Overwintering of herbaceous plants in a changing climate. Still more questions than answers.

PubMed

Rapacz, Marcin; Ergon, Ashild; Höglind, Mats; Jørgensen, Marit; Jurczyk, Barbara; Ostrem, Liv; Rognli, Odd Arne; Tronsmo, Anne Marte

2014-08-01

The increase in surface temperature of the Earth indicates a lower risk of exposure for temperate grassland and crop to extremely low temperatures. However, the risk of low winter survival rate, especially in higher latitudes may not be smaller, due to complex interactions among different environmental factors. For example, the frequency, degree and length of extreme winter warming events, leading to snowmelt during winter increased, affecting the risks of anoxia, ice encasement and freezing of plants not covered with snow. Future climate projections suggest that cold acclimation will occur later in autumn, under shorter photoperiod and lower light intensity, which may affect the energy partitioning between the elongation growth, accumulation of organic reserves and cold acclimation. Rising CO2 levels may also disturb the cold acclimation process. Predicting problems with winter pathogens is also very complex, because climate change may greatly influence the pathogen population and because the plant resistance to these pathogens is increased by cold acclimation. All these factors, often with contradictory effects on winter survival, make plant overwintering viability under future climates an open question. Close cooperation between climatologists, ecologists, plant physiologists, geneticists and plant breeders is strongly required to predict and prevent possible problems. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Human cold stress of strong local-wind "Hijikawa-arashi" in Japan, based on the UTCI index and thermo-physiological responses.

PubMed

Ohashi, Yukitaka; Katsuta, Takumi; Tani, Haruka; Okabayashi, Taiki; Miyahara, Satoshi; Miyashita, Ryoji

2018-03-30

We investigated the cold stress caused by a strong local wind called "Hijikawa-arashi," through in situ vital measurements and the Universal Thermal Climate Index (UTCI). This wind is a very interesting winter phenomenon, localized in an area within 1 km of the seashore in Ozu City, Ehime Prefecture in Japan. When a strong Hijikawa-arashi (HA) occurred at 14-15 m s -1 , the UTCI decreased to - 30 °C along the bridge where commuting residents are the most exposed to strong and cold winds. On the bridge, most participants in our experiment felt "very cold" or "extremely cold." The UTCI of HA can be predicted from a multiple regression equation using wind speed and air temperature. The cold HA wind is also harmful to human thermo-physiological responses. It leads to higher blood pressure and increased heart rate, both of which act as cardiovascular stress triggers. Increases of 6-10 mmHg and 3-6 bpm for every 10 °C reduction in UTCI were seen on all observational days, including HA and non-HA days. In fact, the participants' body skin temperatures decreased by approximately 1.2 to 1.7 °C for every 10 °C reduction in UTCI. Thus, the UTCI variation due to the HA outbreak corresponded well with the cold sensation and thermo-physiological responses in humans. This result suggests that daily UTCI monitoring enables the prediction of thermo-physiological responses to the HA cold stress.

Dual effects of the winter monsoon on haze-fog variations in eastern China

NASA Astrophysics Data System (ADS)

Liu, Qian; Sheng, Lifang; Cao, Ziqi; Diao, Yina; Wang, Wencai; Zhou, Yang

2017-06-01

Previous studies have revealed a negative correlation between the East Asian winter monsoon and wintertime haze-fog events in China. The winter monsoon reduces haze-fog by advecting away aerosol particles and supplying clean air through cold waves. However, it is found that the frequency of haze-fog events on subseasonal time scales displays no correlation with typical winter monsoon indices. The results show that the accumulating and maintaining effects of calm weather related to the Siberian High, which is also a part of the monsoon circulation system, are equally important for the development of haze-fog events during winter. Correlation analysis indicates that subseasonal variations in haze-fog are closely related to the intensity of the Siberian High (r = 0.49). The Siberian High may increase the occurrence of haze-fog events by reducing the near surface wind speed and enhancing the stratification stability. To quantify the contribution of these diverse effects of the winter monsoon on the variations in haze-fog events, we analyzed haze-fog events during periods of cold wave activity and calm weather separately and contrasted the relative contributions of these two effects on different time scales. On the subseasonal scale, the effect of the Siberian High was 2.0 times that of cold waves; on the interannual scale, the effect of cold waves was 2.4 times that of the Siberian High. This study reveals the dual effects of the East Asian winter monsoon on wintertime haze-fog variations in eastern China and provides a more comprehensive understanding of the relationship between the monsoon and haze-fog events.

Preparing for Hiking and Rock-Climbing At Altitude

NASA Technical Reports Server (NTRS)

Greenleaf, John E.

2002-01-01

Exposure to altitude with or without exercise usually results in body dehydration. Psychological and physiological preparation for exercise at altitude involves consideration of maintaining body warmth in a cool to cold environment with progressively lower oxygen content (partial pressure) as altitude increases. However, this discussion will focus on altitudes below 14,000 it where supplemental breathing oxygen is not required for sojourns of healthy people. Background information and helpful advice for those who exercise in the cold can be found in selected articles in the 2001 Winter Issue of this Newsletter: M.B. Ducharme, Get ready for outdoor winter play: prepare yourself for the cold; C. O'Brien, Think layers when dressing for exercise in the cold; B.G. Rice and R. Ellis, Let it snow, let it snow, let it snow - but be aware of winter hazards; and L.B. Mayers, Exercise - induced asthma.

21st Century Trends in the Potential for Ozone Depletion

NASA Astrophysics Data System (ADS)

Hurwitz, M. M.; Newman, P. A.

2009-05-01

We find robust trends in the area where Antarctic stratospheric temperatures are below the threshold for polar stratospheric cloud (PSC) formation in Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) simulations of the 21st century. In late winter (September-October-November), cold area trends are consistent with the respective trends in equivalent effective stratospheric chlorine (EESC), i.e. negative cold area trends in 'realistic future' simulations where EESC decreases and the ozone layer recovers. In the early winter (April through June), regardless of EESC scenario, we find an increasing cold area trend in all simulations; multiple linear regression analysis shows that this early winter cooling trend is associated with the predicted increase in greenhouse gas concentrations in the future. We compare the seasonality of the potential for Antarctic ozone depletion in two versions of the GEOS CCM and assess the impact of the above-mentioned cold area trends on polar stratospheric chemistry.

Variability in winter climate and winter extremes reduces population growth of an alpine butterfly.

PubMed

Roland, Jens; Matter, Stephen F

2013-01-01

We examined the long-term, 15-year pattern of population change in a network of 21 Rocky Mountain populations of Parnassius smintheus butterflies in response to climatic variation. We found that winter values of the broadscale climate variable, the Pacific Decadal Oscillation (PDO) index, were a strong predictor of annual population growth, much more so than were endogenous biotic factors related to population density. The relationship between PDO and population growth was nonlinear. Populations declined in years with extreme winter PDO values, when there were either extremely warm or extremely cold sea surface temperatures in the eastern Pacific relative to that in the western Pacific. Results suggest that more variable winters, and more frequent extremely cold or warm winters, will result in more frequent decline of these populations, a pattern exacerbated by the trend for increasingly variable winters seen over the past century.

Transcriptomic Insights into Phenological Development and Cold Tolerance of Wheat Grown in the Field1[OPEN

PubMed Central

Li, Qiang; Byrns, Brook; Badawi, Mohamed A.; Diallo, Abdoulaye Banire; Danyluk, Jean; Sarhan, Fathey; Zou, Jitao

2018-01-01

Cold acclimation and winter survival in cereal species is determined by complicated environmentally regulated gene expression. However, studies investigating these complex cold responses are mostly conducted in controlled environments that only consider the responses to single environmental variables. In this study, we have comprehensively profiled global transcriptional responses in crowns of field-grown spring and winter wheat (Triticum aestivum) genotypes and their near-isogenic lines with the VRN-A1 alleles swapped. This in-depth analysis revealed multiple signaling, interactive pathways that influence cold tolerance and phenological development to optimize plant growth and development in preparation for a wide range of over-winter stresses. Investigation of genetic differences at the VRN-A1 locus revealed that a vernalization requirement maintained a higher level of cold response pathways while VRN-A1 genetically promoted floral development. Our results also demonstrated the influence of genetic background on the expression of cold and flowering pathways. The link between delayed shoot apex development and the induction of cold tolerance was reflected by the gradual up-regulation of abscisic acid-dependent and C-REPEAT-BINDING FACTOR pathways. This was accompanied by the down-regulation of key genes involved in meristem development as the autumn progressed. The chromosome location of differentially expressed genes between the winter and spring wheat genetic backgrounds showed a striking pattern of biased gene expression on chromosomes 6A and 6D, indicating a transcriptional regulation at the genome level. This finding adds to the complexity of the genetic cascades and gene interactions that determine the evolutionary patterns of both phenological development and cold tolerance traits in wheat. PMID:29259104

A descriptive quantitative study of 7- and 8-year-old children’s outdoor recreation, cold exposure and symptoms in winter in Northern Finland

PubMed Central

Rasi, Hanna; Kuivila, Heli; Pölkki, Tarja; Bloigu, Risto; Rintamäki, Hannu; Tourula, Marjo

2017-01-01

ABSTRACT Background: In Finland, children spend a lot of time outdoors in winter. Outdoor recreation in winter has a wide variety of effects on children’s well-being. Although children are a subgroup that is vulnerable to cold exposure, remarkably little research has been done on the subject. Objective: The aim of this study was to describe children’s outdoor recreation, cold exposure and symptoms in winter in Northern Finland. Design: This was a descriptive quantitative study. The participants consisted of 30 children aged 7–8 years who were living in the provinces of Lapland and Northern Ostrobothnia in Finland. Data were collected by using electronic data-logging thermometers fixed on children’s outerwear for a month. The thermometers recorded the environmental temperature every five minutes and from that temperature data, we were able to discern the exact amount and duration of children’s outdoor recreation. In addition, information on the children’s cold symptoms was collected with structured daily entries. Results: Cold weather was not an obstacle to children’s outdoor activities in Finland. However, the duration of outdoor recreation shortened when the outdoor air temperature decreased. There were no significant differences between boys and girls in terms of time spent outdoors. Remarkably, every child reported symptoms associated with cold. Almost half of the children reported experiencing respiratory symptoms and some children also experienced cold pain and numbness. Conclusions: The results of this study illustrate the many and varied effects that cold exposure can have on children’s health and well-being. In order to prevent negative health effects of cold exposure on children, structured prevention strategies are needed: therefore, children’s exposure to cold should be studied more. Future research should also bring out more the positive health effects of outdoor recreation on children’s growth and development.​​​​ PMID:28346080

Tolerance of subzero winter cold in kudzu (Pueraria montana var. lobata) and its implications for northward migration in a warming climate

USDA-ARS?s Scientific Manuscript database

Kudzu (Pueraria montana var. lobata) is an important invasive species that was planted throughout southeastern North America until the mid-20th century. Winter survival is commonly assumed to control its distribution; however, its cold tolerance thresholds have not been determined. Here, we used bio...

Winter Weather Emergencies

MedlinePlus

Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

Past and future hydro-climatic change and the 2015 drought in the interior of western Canada

NASA Astrophysics Data System (ADS)

DeBeer, C. M.; Wheater, H. S.; Pomeroy, J. W.; Stewart, R. E.; Szeto, K.; Brimelow, J.; Chun, K. P.; Masud, M. B.; Bonsal, B. R.

2015-12-01

The interior of western Canada has experienced rapid and severe hydro-climatic change in recent decades. This is projected to continue in future. Since 1950, mean annual air temperature has increased by 2 °C (4 °C increase in winter daily means) with associated changes in cryospheric regime. Changes in precipitation have varied regionally; in the Prairies there has been a decrease in winter precipitation, shift from snowfall to rainfall, and increased clustering of summer rainfall events into multiple day storms. Regionally, river discharge indicates an earlier spring freshet and increased incidence of rain-on-snow peak flow events, but otherwise mixed responses due to multiple process interactions. In winter/spring 2015, persistent anomalous ridging conditions developed over western North America causing widespread drought. This produced abnormally warm and dry conditions over the Rocky Mountain headwaters of the Mackenzie and Saskatchewan Rivers, resulting in low spring snowpacks that melted earlier than normal and were followed by an atypical lack of spring rainfall. By summer 2015, most of western Canada was subject to extreme drought conditions leading to record dry soil moisture conditions in parts of the Prairies during a key crop growth time, streamflows that were greatly diminished, and extensive wildfires across the Boreal Forest. The importance of the warmer winter to this drought and the contextual trend for increasing winter warmth provide new insight into the impact of climate warming on droughts in cold regions. This talk will discuss efforts by the Changing Cold Regions Network (CCRN; www.ccrnetwork.ca) to understand and diagnose the 2015 drought, its potential linkages with the concurrent California drought and other continental events, and its relevance in the context of historical and predicted future climate change.

Snow in Time for the Solstice

NASA Technical Reports Server (NTRS)

2004-01-01

In mid-December, the weather in eastern North America cooperated with the calendar, and a wintry blast from the Arctic delivered freezing cold air, blustery winds, and snow just in time for the Winter Solstice on December 21' the Northern Hemisphere's longest night of the year and the official start of winter. This image was captured by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on December 20, 2004, the day after an Arctic storm dove down into the United States, bringing snow to New England (upper right of top image); the coastal mid-Atlantic, including Washington, D.C.; and the southern Appalachian Mountains in Tennessee and North Carolina. Over the Atlantic Ocean (image right), the fierce Arctic winds were raking the clouds into rows, like a gardener getting ready to plant the seeds of winter. The detailed close-up at the bottom of this image pair shows the cloud and snow patterns around Lake Ontario, illustrating the occurrence of 'lake-effect snow.' Areas in western upstate New York often get as much as fifteen feet or more of snow each year as cold air from Canada and the Arctic sweeps down over the relatively warm waters of Lakes Ontario and Erie. Cold air plus moisture from the lakes equals heavy snow. Since the wind generally blows from west to east, it is the 'downwind' cities like Buffalo and Rochester that receive the heaping helpings of snowfall, while cities on the upwind side of the lake, such as Toronto, receive much less. Unlike storms that begin with specific low-pressure systems in the Pacific Ocean and march eastward across the Pacific Northwest, the Rockies, the Great Plains, and sometimes the East, the lake-effect snows aren't tied to a specific atmospheric disturbance. They are more a function of geography, which means that the lakes can keep fueling snow storms for as long as they remain ice-free in early winter, as well as when they begin to thaw in late winter and early spring. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE.

Changes in extreme cold tolerance, membrane composition and cardiac transcriptome during the first day of thermal acclimation in the porcelain crab Petrolisthes cinctipes.

PubMed

Ronges, Daria; Walsh, Jillian P; Sinclair, Brent J; Stillman, Jonathon H

2012-06-01

Intertidal zone organisms can experience transient freezing temperatures during winter low tides, but their extreme cold tolerance mechanisms are not known. Petrolisthes cinctipes is a temperate mid-high intertidal zone crab species that can experience wintertime habitat temperatures below the freezing point of seawater. We examined how cold tolerance changed during the initial phase of thermal acclimation to cold and warm temperatures, as well as the persistence of cold tolerance during long-term thermal acclimation. Thermal acclimation for as little as 6 h at 8°C enhanced cold tolerance during a 1 h exposure to -2°C relative to crabs acclimated to 18°C. Potential mechanisms for this enhanced tolerance were elucidated using cDNA microarrays to probe for differences in gene expression in cardiac tissue of warm- and cold-acclimated crabs during the first day of thermal acclimation. No changes in gene expression were detected until 12 h of thermal acclimation. Genes strongly upregulated in warm-acclimated crabs represented immune response and extracellular/intercellular processes, suggesting that warm-acclimated crabs had a generalized stress response and may have been remodelling tissues or altering intercellular processes. Genes strongly upregulated in cold-acclimated crabs included many that are involved in glucose production, suggesting that cold acclimation involves increasing intracellular glucose as a cryoprotectant. Structural cytoskeletal proteins were also strongly represented among the genes upregulated in only cold-acclimated crabs. There were no consistent changes in composition or the level of unsaturation of membrane phospholipid fatty acids with cold acclimation, which suggests that neither short- nor long-term changes in cold tolerance are mediated by changes in membrane fatty acid composition. Overall, our study demonstrates that initial changes in cold tolerance are likely not regulated by transcriptomic responses, but that gene-expression-related changes in homeostasis begin within 12 h, the length of a tidal cycle.

Daily and seasonal activity patterns in the eastern gray squirrel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bland, M.E.

1977-03-01

The daily and seasonal activity patterns of the eastern gray squirrel were investigated between July 1, 1971 and September 16, 1972. Seasonal variations existed in the amount of time per day squirrels were active, the time of onset and cessation of activity, and the size of home range. Squirrels were most active in the fall and spring and least active in the winter. Two peaks in activity (morning and evening) with a mid-day resting period were characteristic of the summer activity pattern. During the winter one brief period of activity occurred during the warm mid-day hours. In the fall themore » time of onset of activity was consistent and occurred 20 to 30 minutes before sunrise. Cessation of activity was also regular and took place 20 to 30 minutes after sunset. Times of onset and cessation of activity were irregular during the winter and summer with onset usually occurring after sunrise and cessation before sunset. Home range size was smallest in winter and largest in late spring and late summer. Male and female range sizes were similar in fall and winter but in the spring and summer ranges of males exceeded those of females. During winter one night nest location was used per given two week period and daytime activity was restricted to the area around the den site. In spring, summer, and fall each squirrel used between two and three nest locations per two week period and squirrels traveled considerable distance from the den site. Hardwood and cedar forests were heavily utilized by the squirrels with approximately 53 percent of the locations occurring in hardwood forests and 38 percent in cedar forests. Correlations between the amount of time per day squirrels were active and various abiotic and biotic factors were made. Snow cover and/or extremely cold temperatures during the winter and early spring curtailed movement, and rainy weather in summer decreased activity. The availability of acorns in the autumn and the appearance of food in the spring increased movement.« less

Assessment of long-term monthly and seasonal trends of warm (cold), wet (dry) spells in Kansas, USA

NASA Astrophysics Data System (ADS)

Dokoohaki, H.; Anandhi, A.

2013-12-01

A few recent studies have focused on trends in rainfall, temperature, and frost indicators at different temporal scales using centennial weather station data in Kansas; our study supplements this work by assessing the changes in spell indicators in Kansas. These indicators provide the duration between temperature-based (warm and cold) and precipitation-based (wet and dry) spells. For wet (dry) spell calculations, a wet day is defined as a day with precipitation ≥1 mm, and a dry day is defined as one with precipitation ≤1 mm. For warm (cold) spell calculations, a warm day is defined as a day with maximum temperature >90th percentile of daily maximum temperature, and a cold day is defined as a day with minimum temperature <10th percentile of daily minimum temperature. The percentiles are calculated for 1971-2000, and four spell indicators are calculated: Average Wet Spell Length (AWSL), Dry Spell Length (ADSL), Average Warm Spell Days (AWSD) and Average Cold Spell Days (ACSD) are calculated. Data were provided from 23 centennial weather stations across Kansas, and all calculations were done for four time periods (through 1919, 1920-1949, 1950-1979, and 1980-2009). The definitions and software provided by Expert Team on Climate Change Detection and Indices (ETCCDI) were adapted for application to Kansas. The long- and short-term trends in these indices were analyzed at monthly and seasonal timescales. Monthly results indicate that ADSL is decreasing and AWSL is increasing throughout the state. AWSD and ACSD both showed an overall decreasing trend, but AWSD trends were variable during the beginning of the Industrial Revolution. Results of seasonal analysis revealed that the fall season recorded the greatest increasing trend for ACSD and the greatest decreasing trend for AWSD across the whole state and during all time periods. Similarly, the greatest increasing and decreasing trends occurred in winter for AWSL and ADSL, respectively. These variations can be important indicators of climatic change that may not be represented in mean conditions. Detailed geographical and temporal variations of the spell indices also can be beneficial for updating management decisions and providing adaptation recommendations for local and regional agricultural production.

Possible mechanisms for four regimes associated with cold events over East Asia

NASA Astrophysics Data System (ADS)

Yang, Zifan; Huang, Wenyu; Wang, Bin; Chen, Ruyan; Wright, Jonathon S.; Ma, Wenqian

2017-09-01

Circulation patterns associated with cold events over East Asia during the winter months of 1948-2014 are classified into four regimes by applying a k-means clustering method based on the area-weighted pattern correlation. The earliest precursor signals for two regimes are anticyclonic anomalies, which evolve into Ural and central Siberian blocking-like circulation patterns. The earliest precursor signals for the other two regimes are cyclonic anomalies, both of which evolve to amplify the East Asian trough (EAT). Both the blocking-like circulation patterns and amplified EAT favor the initialization of cold events. On average, the blocking-related regimes tend to last longer. The lead time of the earliest precursor signal for the central Siberian blocking-related regime is only 4 days, while those for the other regimes range from 16 to 18 days. The North Atlantic Oscillation plays essential roles both in triggering the precursor for the Ural blocking-related regime and in amplifying the precursors for all regimes. All regimes preferentially occur during the positive phase of the Eurasian teleconnection pattern and the negative phase of the El Niño-Southern Oscillation. For three regimes, surface cooling is primarily due to reduced downward infrared radiation and enhanced cold advection. For the remaining regime, which is associated with the southernmost cooling center, sensible and latent heat release and horizontal cold advection dominate the East Asian cooling.

Documentary evidence of climate variability during cold seasons in Lesotho, southern Africa, 1833-1900

NASA Astrophysics Data System (ADS)

Grab, Stefan W.; Nash, David J.

2010-03-01

This study presents the first 19th century cold season climate chronology for the Kingdom of Lesotho in southern Africa. The chronology is constructed using a variety of documentary sources including letters, diaries, reports, monographs and newspaper articles obtained from southern African and British archives. Information relating to cold season weather phenomena during the austral autumn, winter and early spring months were recorded verbatim. Each of the cold seasons from 1833 to 1900 was then classified as “very severe”, “severe” or “normal/mild”, with a confidence rating ranging from low (1) to high (3) awarded against each annual classification. The accuracy of the document-derived chronology was verified against temperature data for Maseru for the period 1893-1900. Excellent correspondence of the document-derived chronology with the Maseru instrumental data and also with other global proxy temperature records for the 19th century is achieved. The results indicate 12 (18% of the total) very severe, 16 (23%) severe and 40 (59%) normal/mild cold seasons between 1833 and 1900. The overall trend is for more severe and snow-rich cold seasons during the early part of the study period (1833-1854) compared with the latter half of the 19th century (with the exception of the 1880s). A reduction in the duration of the frost season by over 20 days during the 19th century is also tentatively identified. Several severe to very severe cold seasons in Lesotho follow after major tropical and SH volcanic eruptions; such years are usually characterized by early frosts, and frequent and heavy snowfalls. The blocking of solar radiation and the enhanced northward displacement of polar fronts that are directly or indirectly associated with volcanic events, may account for many of the most severe Lesotho winters during the 19th century.

Gene expression analysis to understand cold tolerance in citrus

USDA-ARS?s Scientific Manuscript database

Citrus cultivars show a wide range of tolerance to cold temperatures. Lemons and limes are known to be sensitive to cold while certain mandarins and trifoliate oranges can endure severe winters. To understand the mechanism of cold tolerance in citrus, we selected three known cold-sensitive and three...

Upper lethal temperatures in three cold-tolerant insects are higher in winter than in summer.

PubMed

Vu, Henry M; Duman, John G

2017-08-01

Upper lethal temperatures (ULTs) of cold-adapted insect species in winter have not been previously examined. We anticipated that as the lower lethal temperatures (LLTs) decreased (by 20-30°C) with the onset of winter, the ULTs would also decrease accordingly. Consequently, given the recent increases in winter freeze-thaw cycles and warmer winters due to climate change, it became of interest to determine whether ambient temperatures during thaws were approaching ULTs during the cold seasons. However, beetle Dendroides canadensis (Coleoptera: Pyrochroidae) larvae had higher 24 and 48 h ULT 50 (the temperature at which 50% mortality occurred) in winter than in summer. The 24 and 48 h ULT 50 for D. canadensis in winter were 40.9 and 38.7°C, respectively. For D. canadensis in summer, the 24 and 48 h ULT 50 were 36.7 and 36.4°C. During the transition periods of spring and autumn, the 24 h ULT 50 was 37.3 and 38.5°C, respectively. While D. canadensis in winter had a 24 h LT 50 range between LLT and ULT of 64°C, the summer range was only 41°C. Additionally, larvae of the beetle Cucujus clavipes clavipes (Coleoptera: Cucujidae) and the cranefly Tipula trivittata (Diptera: Tipulidae) also had higher ULTs in winter than in summer. This unexpected phenomenon of increased temperature survivorship at both lower and higher temperatures in the winter compared with that in the summer has not been previously documented. With the decreased high temperature tolerance as the season progresses from winter to summer, it was observed that environmental temperatures are closest to upper lethal temperatures in spring. © 2017. Published by The Company of Biologists Ltd.

Cold truths: how winter drives responses of terrestrial organisms to climate change.

PubMed

Williams, Caroline M; Henry, Hugh A L; Sinclair, Brent J

2015-02-01

Winter is a key driver of individual performance, community composition, and ecological interactions in terrestrial habitats. Although climate change research tends to focus on performance in the growing season, climate change is also modifying winter conditions rapidly. Changes to winter temperatures, the variability of winter conditions, and winter snow cover can interact to induce cold injury, alter energy and water balance, advance or retard phenology, and modify community interactions. Species vary in their susceptibility to these winter drivers, hampering efforts to predict biological responses to climate change. Existing frameworks for predicting the impacts of climate change do not incorporate the complexity of organismal responses to winter. Here, we synthesise organismal responses to winter climate change, and use this synthesis to build a framework to predict exposure and sensitivity to negative impacts. This framework can be used to estimate the vulnerability of species to winter climate change. We describe the importance of relationships between winter conditions and performance during the growing season in determining fitness, and demonstrate how summer and winter processes are linked. Incorporating winter into current models will require concerted effort from theoreticians and empiricists, and the expansion of current growing-season studies to incorporate winter. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.

Development of a new USDA plant hardiness zone map for the United States

Treesearch

C. Daly; M.P. Widrlechner; M.D. Halbleib; J.I. Smith; W.P. Gibson

2012-01-01

In many regions of the world, the extremes of winter cold are a major determinant of the geographic distribution of perennial plant species and of their successful cultivation. In the United States, the U.S. Department of Agriculture (USDA) Plant Hardiness Zone Map (PHZM) is the primary reference for defining geospatial patterns of extreme winter cold for the...

Large-scale evaluation of pea (Pisum sativum L.) germplasm for cold tolerance in the open field during winter in Qingdao.

USDA-ARS?s Scientific Manuscript database

As a cool season crop, pea (Pisum sativum L.) can tolerate frost at the vegetative stage but has yield loss when freezing stress occurs at reproductive stage. Cold tolerance improvement of pea varieties is important for the stable yield and the expansion of winter pea planting area. Under the natura...

Impact of cold climates on vehicle emissions: the cold start air toxics pulse : final report.

DOT National Transportation Integrated Search

2016-09-21

This project measured cold start emissions from four vehicles in winter using fast response instrumentation to accurately measure the : time variation of the cold start emission pulse. Seventeen successful tests were conducted over a temperature rang...

Seasonal habitat selection by lake trout (Salvelinus namaycush) in a small Canadian shield lake: Constraints imposed by winter conditions

USGS Publications Warehouse

Blanchfield, P.J.; Tate, L.S.; Plumb, J.M.; Acolas, M.-L.; Beaty, K.G.

2009-01-01

The need for cold, well-oxygenated waters significantly reduces the habitat available for lake trout (Salvelinus namaycush) during stratification of small temperate lakes. We examined the spatial and pelagic distribution of lake trout over two consecutive summers and winters and tested whether winter increased habitat availability and access to littoral regions in a boreal shield lake in which pelagic prey fish are absent. In winter, lake trout had a narrowly defined pelagic distribution that was skewed to the upper 3 m of the water column and spatially situated in the central region of the lake. Individual core areas of use (50% Kernel utilization distributions) in winter were much reduced (75%) and spatially non-overlapping compared to summer areas, but activity levels were similar between seasons. Winter habitat selection is in contrast to observations from the stratified season, when lake trout were consistently located in much deeper waters (>6 m) and widely distributed throughout the lake. Winter distribution of lake trout appeared to be strongly influenced by ambient light levels; snow depth and day length accounted for up to 69% of the variation in daily median fish depth. More restricted habitat use during winter than summer was in contrast to our original prediction and illustrates that a different suite of factors influence lake trout distribution between these seasons. ?? Springer Science+Business Media B.V. 2009.

Winter cold-tolerance thresholds in field-grown Miscanthus hybrid rhizomes

PubMed Central

Peixoto, Murilo de Melo; Friesen, Patrick Calvin; Sage, Rowan F.

2015-01-01

The cold tolerance of winter-dormant rhizomes was evaluated in diploid, allotriploid, and allotetraploid hybrids of Miscanthus sinensis and Miscanthus sacchariflorus grown in a field setting. Two artificial freezing protocols were tested: one lowered the temperature continuously by 1°C h–1 to the treatment temperature and another lowered the temperature in stages of 24h each to the treatment temperature. Electrolyte leakage and rhizome sprouting assays after the cold treatment assessed plant and tissue viability. Results from the continuous-cooling trial showed that Miscanthus rhizomes from all genotypes tolerated temperatures as low as –6.5 °C; however, the slower, staged-cooling procedure enabled rhizomes from two diploid lines to survive temperatures as low as –14 °C. Allopolyploid genotypes showed no change in the lethal temperature threshold between the continuous and staged-cooling procedure, indicating that they have little ability to acclimate to subzero temperatures. The results demonstrated that rhizomes from diploid Miscanthus lines have superior cold tolerance that could be exploited to improve performance in more productive polyploid lines. With expected levels of soil insulation, low winter air temperatures should not harm rhizomes of tolerant diploid genotypes of Miscanthus in temperate to sub-boreal climates (up to 60°N); however, the observed winter cold in sub-boreal climates could harm rhizomes of existing polyploid varieties of Miscanthus and thus reduce stand performance. PMID:25788733

Long-range transport of Asian pollution to the northeast Pacific: Seasonal variations and transport pathways of carbon monoxide

NASA Astrophysics Data System (ADS)

Liang, Qing; Jaeglé, Lyatt; Jaffe, Daniel A.; Weiss-Penzias, Peter; Heckman, Anna; Snow, Julie A.

2004-12-01

Continuous CO measurements were obtained at Cheeka Peak Observatory (CPO, 48.3°N, 124.6°W, 480 m), a coastal site in Washington state, between 9 March 2001 and 31 May 2002. We analyze these observations as well as CO observations at ground sites throughout the North Pacific using the GEOS-CHEM global tropospheric chemistry model to examine the seasonal variations of Asian long-range transport. The model reproduces the observed CO levels, their seasonal cycle and day-to-day variability, with a 5-20 ppbv negative bias in winter/spring and 5-10 ppbv positive bias during summer. Asian influence on CO levels in the North Pacific troposphere maximizes during spring and minimizes during summer, ranging from 91 ppbv (44% of total CO) to 52 ppbv (39%) along the Asian Pacific Rim and from 44 ppbv (30%) to 24 ppbv (23%) at CPO. Maximum export of Asian pollution to the western Pacific occurs at 20°-50°N during spring throughout the tropospheric column, shifting to 30°-60°N during summer, mostly in the upper troposphere. The model captures five particularly strong transpacific transport events reaching CPO (four in spring, one in winter) resulting in 20-40 ppbv increases in observed CO levels. Episodic long-range transport of pollutants from Asia to the NE Pacific occurs throughout the year every 10, 15, and 30 days in the upper, middle, and lower troposphere, respectively. Lifting ahead of cold fronts followed by transport in midlatitude westerlies accounts for 78% of long-range transport events reaching the NE Pacific middle and upper troposphere. During summer, convective injection into the upper troposphere competes with frontal mechanisms in this export. Most events reaching the NE Pacific lower troposphere below 2 km altitude result from boundary layer outflow behind cold fronts (for spring) or ahead of cold fronts (for other seasons) followed by low-level transpacific transport.

Chemical and Dynamical Impacts of Stratospheric Sudden Warmings on Arctic Ozone Variability

NASA Technical Reports Server (NTRS)

Strahan, S. E.; Douglass, A. R.; Steenrod, S. D.

2016-01-01

We use the Global Modeling Initiative (GMI) chemistry and transport model with Modern-Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields to quantify heterogeneous chemical ozone loss in Arctic winters 2005-2015. Comparisons to Aura Microwave Limb Sounder N2O and O3 observations show the GMI simulation credibly represents the transport processes and net heterogeneous chemical loss necessary to simulate Arctic ozone. We find that the maximum seasonal ozone depletion varies linearly with the number of cold days and with wave driving (eddy heat flux) calculated from MERRA fields. We use this relationship and MERRA temperatures to estimate seasonal ozone loss from 1993 to 2004 when inorganic chlorine levels were in the same range as during the Aura period. Using these loss estimates and the observed March mean 63-90N column O3, we quantify the sensitivity of the ozone dynamical resupply to wave driving, separating it from the sensitivity of ozone depletion to wave driving. The results show that about 2/3 of the deviation of the observed March Arctic O3 from an assumed climatological mean is due to variations in O3 resupply and 13 is due to depletion. Winters with a stratospheric sudden warming (SSW) before mid-February have about 1/3 the depletion of winters without one and export less depletion to the midlatitudes. However, a larger effect on the spring midlatitude ozone comes from dynamical differences between warm and cold Arctic winters, which can mask or add to the impact of exported depletion.

Adaptations to polar life in mammals and birds.

PubMed

Blix, Arnoldus Schytte

2016-04-15

This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals and birds to the challenges of polar life. The polar environment may be characterized by grisly cold, scarcity of food and darkness in winter, and lush conditions and continuous light in summer. Resident animals cope with these changes by behavioural, physical and physiological means. These include responses aimed at reducing exposure, such as 'balling up', huddling and shelter building; seasonal changes in insulation by fur, plumage and blubber; and circulatory adjustments aimed at preservation of core temperature, to which end the periphery and extremities are cooled to increase insulation. Newborn altricial animals have profound tolerance to hypothermia, but depend on parental care for warmth, whereas precocial mammals are well insulated and respond to cold with non-shivering thermogenesis in brown adipose tissue, and precocial birds shiver to produce heat. Most polar animals prepare themselves for shortness of food during winter by the deposition of large amounts of fat in times of plenty during autumn. These deposits are governed by a sliding set-point for body fatness throughout winter so that they last until the sun reappears in spring. Polar animals are, like most others, primarily active during the light part of the day, but when the sun never sets in summer and darkness prevails during winter, high-latitude animals become intermittently active around the clock, allowing opportunistic feeding at all times. The importance of understanding the needs of the individuals of a species to understand the responses of populations in times of climate change is emphasized. © 2016. Published by The Company of Biologists Ltd.

Seasonal change in the capacity for supercooling by neonatal painted turtles.

PubMed

Packard, G C; Packard, M J; McDaniel, L L

2001-05-01

Hatchlings of the North American painted turtle (Chrysemys picta) typically spend their first winter of life inside the shallow, subterranean nest where they completed incubation the preceding summer. This facet of their natural history commonly causes neonates in northerly populations to be exposed in mid-winter to ice and cold, which many animals survive by remaining unfrozen and supercooled. We measured the limit of supercooling in samples of turtles taken shortly after hatching and in other samples after 2 months of acclimation (or acclimatization) to a reduced temperature in the laboratory or field. Animals initially had only a limited capacity for supercooling, but they acquired an ability to undergo deeper supercooling during the course of acclimation. The gut of most turtles was packed with particles of soil and eggshell shortly after hatching, but not after acclimation. Thus, the relatively high limit of supercooling for turtles in the days immediately after hatching may have resulted from the ingestion of soil (and associated nucleating agents) by the animals as they were freeing themselves from their eggshell, whereas the relatively low limit of supercooling attained by acclimated turtles may have resulted from their purging their gut of its contents. Parallels may, therefore, exist between the natural-history strategy expressed by hatchling painted turtles and that expressed by numerous terrestrial arthropods that withstand the cold of winter by sustaining a state of supercooling.

Molecular characterization of three Hsp90 from Pieris and expression patterns in response to cold and thermal stress in summer and winter diapause of Pieris melete.

PubMed

Wu, Yue-Kun; Zou, Chao; Fu, Dao-Meng; Zhang, Wan-Na; Xiao, Hai-Jun

2018-04-01

Heat shock proteins (Hsps) have been linked to stresses and winter diapause in insects, but whether they are components of summer diapause is still unknown. In this study, complementary DNAs of Hsp90 from Pieris melete, Pieris rapae and Pieris canidia named PmHsp90, PrHsp90 and PcHsp90, respectively, were cloned and sequenced. The deduced amino acid sequence consisted of 718 amino acid residues with a putative molecular mass of 82.6, 82.6 and 82.7 kDa, respectively. The amino acid sequences contained all of the five conserved signature motifs in the Hsp90 family and a bHLH protein folding activity region. The differential expression pattern of PmHsp90 in response to summer diapause and winter diapause, which are related to heat/cold stress, was investigated. Cold stress induced Hsp90 up-regulation in summer and winter diapause pupae, but not in non-diapause individuals. Heat shock up-regulated PmHsp90 gradually with an increase in temperature in summer diapause, and PmHsp90 was rapidly up-regulated in winter diapause. After 30 min heat shock at 39°C, substantial up-regulation of PmHsp90 transcript levels were observed both in summer and winter diapause. However, in non-diapause a relatively stable expression was found under different durations of 39°C heat shock. Compared to the optimal treatment of 18°C for diapause development, a high temperature acclimation of 31°C induced PmHsp90 up-regulation in summer diapause, whereas a low temperature acclimation of 4°C induced up-regulation in winter diapause. The current results indicate that Hsp90 may play an important role in response to heat/cold stress both in summer and winter diapause. © 2016 Institute of Zoology, Chinese Academy of Sciences.

The impact of the 2008 cold spell on mortality in Shanghai, China

NASA Astrophysics Data System (ADS)

Ma, Wenjuan; Yang, Chunxue; Chu, Chen; Li, Tiantian; Tan, Jianguo; Kan, Haidong

2013-01-01

No prior studies in China have investigated the health impact of cold spell. In Shanghai, we defined the cold spell as a period of at least seven consecutive days with daily temperature below the third percentile during the study period (2001-2009). Between January 2001 and December 2009, we identified a cold spell between January 27 and February 3, 2008 in Shanghai. We investigated the impact of cold spell on mortality of the residents living in the nine urban districts of Shanghai. We calculated the excess deaths and rate ratios (RRs) during the cold spell and compared these data with a winter reference period (January 6-9, and February 28 to March 2). The number of excess deaths during the cold spell period was 153 in our study population. The cold spell caused a short-term increase in total mortality of 13 % (95 % CI: 7-19 %). The impact was statistically significant for cardiovascular mortality (RR = 1.21, 95 % CI: 1.12-1.31), but not for respiratory mortality (RR = 1.14, 95 % CI: 0.98-1.32). For total mortality, gender did not make a statistically significant difference for the cold spell impact. Cold spell had a significant impact on mortality in elderly people (over 65 years), but not in other age groups. Conclusively, our analysis showed that the 2008 cold spell had a substantial effect on mortality in Shanghai. Public health programs should be tailored to prevent cold-spell-related health problems in the city.

Effect of farm and simulated laboratory cold environmental conditions on the performance and physiological responses of lactating dairy cows supplemented with bovine somatotropin (BST)

NASA Astrophysics Data System (ADS)

Becker, B. A.; Johnson, H. D.; Li, R.; Collier, R. J.

1990-09-01

A study was conducted to evaluate the effect of bovine somatotropin (BST) supplementation in twelve lactating dairy cows maintained in cold environmental conditions. Six cows were injected daily with 25 mg of BST; the other six were injected with a control vehicle. Cows were maintained under standard dairy management during mid-winter for 30 days. Milk production was recorded twice daily, and blood samples were taken weekly. Animals were then transferred to environmentally controlled chambers and exposed to cycling thermoneutral (15° to 20° C) and cycling cold (-5° to +5° C) temperatures for 10 days in a split-reversal design. Milk production, feed and water intake, body weights and rectal temperatures were monitored. Blood samples were taken on days 1, 3, 5, 8 and 10 of each period and analyzed for plasma triiodothyronine (T3), thyroxine (T4), cortisol, insulin and prolactin. Under farm conditions, BST-treated cows produced 11% more milk than control-treated cows and in environmentally controlled chambers produced 17.4% more milk. No differences due to BST in feed or water intake, body weights or rectal temperatures were found under laboratory conditions. Plasma T3 and insulin increased due to BST treatment while no effect was found on cortisol, prolactin or T4. The results showed that the benefits of BST supplementation in lactating dairy cows were achieved under cold environmental conditions.

Come rain or shine: Multi-model Projections of Climate Hazards affecting Transportation in the South Central United States

NASA Astrophysics Data System (ADS)

Mullens, E.; Mcpherson, R. A.

2016-12-01

This work develops detailed trends in climate hazards affecting the Department of Transportation's Region 6, in the South Central U.S. Firstly, a survey was developed to gather information regarding weather and climate hazards in the region from the transportation community, identifying key phenomena and thresholds to evaluate. Statistically downscaled datasets were obtained from the Multivariate Adaptive Constructed Analogues (MACA) project, and the Asynchronous Regional Regression Model (ARRM), for a total of 21 model projections, two coupled model intercomparisons (CMIP3, and CMIP5), and four emissions pathways (A1Fi, B1, RCP8.5, RCP4.5). Specific hazards investigated include winter weather, freeze-thaw cycles, hot and cold extremes, and heavy precipitation. Projections for each of these variables were calculated for the region, utilizing spatial mapping, and time series analysis at the climate division level. The results indicate that cold-season phenomena such as winter weather, freeze-thaw, and cold extremes, decrease in intensity and frequency, particularly with the higher emissions pathways. Nonetheless, specific model and downscaling method yields variability in magnitudes, with the most notable decreasing trends late in the 21st century. Hot days show a pronounced increase, particularly with greater emissions, producing annual mean 100oF day frequencies by late 21st century analogous to the 2011 heatwave over the central Southern Plains. Heavy precipitation, evidenced by return period estimates and counts-over-thresholds, also show notable increasing trends, particularly between the recent past through mid-21st Century. Conversely, mean precipitation does not show significant trends and is regionally variable. Precipitation hazards (e.g., winter weather, extremes) diverge between downscaling methods and their associated model samples much more substantially than temperature, suggesting that the choice of global model and downscaled data is particularly important when considering region-specific impacts for precipitation. These results are intended to inform region transportation professionals of the susceptibility of the area to climate extremes, and to be a resource for assessing and incorporating changing risk probabilities into their planning processes.

Winter drought impairs xylem phenology, anatomy and growth in Mediterranean Scots pine forests.

PubMed

Camarero, J J; Guada, G; Sánchez-Salguero, R; Cervantes, E

2016-12-01

Continental Mediterranean forests face drought but also cold spells and both climate extremes can impair the resilience capacity of these forests. Climate warming could amplify the negative effects of cold spells by inducing premature dehardening. Here we capitalize on a winter drought-induced dieback triggered by a cold spell which occurred in December 2001 affecting Scots pine forests in eastern Spain. We assessed post-dieback recovery by quantifying and comparing radial growth and xylem anatomy of non-declining (ND, crown cover >50%) and declining (D, crown cover ≤50%) trees in two sites (VP, Villarroya de los Pinares; TO, Torrijas). We also characterized xylogenesis in both sites and aboveground productivity in site VP. Dieback caused legacy effects since needle loss, a 60% reduction in litter fall and radial-growth decline characterized D-trees 3 years after dieback symptoms started appearing in spring 2002. D-trees formed collapsed tracheids in the 2002-ring, particularly in the most affected VP site where xylogenesis differences between ND and D trees were most noticeable. The lower growth rates of D-trees were caused by a shorter duration of their major xylogenesis phases. In site VP the radial-enlargement and wall-thickening of tracheids were significantly reduced in D-trees as compared to ND-trees because these xylogenesis phases tended to start earlier and end later in ND-trees. Gompertz models fitted to tracheid production predicted that maximum growth rates occurred 11-12 days earlier in ND than in D-trees. The formation of radially-enlarging tracheids was enhanced by longer days in both study sites and also by wetter conditions in the driest TO site, but xylogenesis sensitivity to climate was reduced in D-trees. Winter-drought dieback impairs xylem anatomy and phenology, aboveground productivity, xylogenesis and growth in Mediterranean Scots pine populations. Affected stands show a costly post-dieback recovery challenging their resilience ability. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Plasticity in body temperature and metabolic capacity sustains winter activity in a small endotherm (Rattus fuscipes).

PubMed

Glanville, Elsa J; Seebacher, Frank

2010-03-01

Small mammals that remain active throughout the year at a constant body temperature have a much greater energy and food requirement in winter. Lower body temperatures in winter may offset the increased energetic cost of remaining active in the cold, if cellular metabolism is not constrained by a negative thermodynamic effect. We aimed to determine whether variable body temperatures can be advantageous for small endotherms by testing the hypothesis that body temperature fluctuates seasonally in a wild rat (Rattus fuscipes); conferring an energy saving and reducing food requirements during resource restricted winter. Additionally we tested whether changes in body temperature affected tissue specific metabolic capacity. Winter acclimatized rats had significantly lower body temperatures and thicker fur than summer acclimatized rats. Mitochondrial oxygen consumption and the activity of enzymes that control oxidative (citrate synthase, cytochrome c-oxidase) and anaerobic (lactate dehydrogenase) metabolism were elevated in winter and were not negatively affected by the lower body temperature. Energy transfer modeling showed that lower body temperatures in winter combined with increased fur thickness to confer a 25 kJ day(-1) energy saving, with up to 50% owing to reduced body temperature alone. We show that phenotypic plasticity at multiple levels of organization is an important component of the response of a small endotherm to winter. Mitochondrial function compensates for lower winter body temperatures, buffering metabolic heat production capacity. Copyright 2009 Elsevier Inc. All rights reserved.

Evaluation of cold mixes for winter pothole repair.

DOT National Transportation Integrated Search

1995-01-01

This study was conducted to evaluate the performance of 13 proprietary cold-mix patching materials, 4 of which are currently approved under a Virginia Department of Transportation (VDOT) Special Provision for High Quality Cold Patching Materials. Col...

Tolerance to multiple climate stressors: A case study of Douglas-fir drought and cold hardiness

USGS Publications Warehouse

Bansal, Sheel; Harrington, Constance A; St. Clair, John Bradley

2016-01-01

Summary: 1. Drought and freeze events are two of the most common forms of climate extremes which result in tree damage or death, and the frequency and intensity of both stressors may increase with climate change. Few studies have examined natural covariation in stress tolerance traits to cope with multiple stressors among wild plant populations. 2. We assessed the capacity of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii), an ecologically and economically important species in the northwestern USA, to tolerate both drought and cold stress on 35 populations grown in common gardens. We used principal components analysis to combine drought and cold hardiness trait data into generalized stress hardiness traits to model geographic variation in hardiness as a function of climate across the Douglas-fir range. 3. Drought and cold hardiness converged among populations along winter temperature gradients and diverged along summer precipitation gradients. Populations originating in regions with cold winters had relatively high tolerance to both drought and cold stress, which is likely due to overlapping adaptations for coping with winter desiccation. Populations from regions with dry summers had increased drought hardiness but reduced cold hardiness, suggesting a trade-off in tolerance mechanisms. 4. Our findings highlight the necessity to look beyond bivariate trait–climate relationships and instead consider multiple traits and climate variables to effectively model and manage for the impacts of climate change on widespread species.

Meteorological characteristics and overland precipitation impacts of atmospheric rivers affecting the West coast of North America based on eight years of SSM/I satellite observations

USGS Publications Warehouse

Neiman, P.J.; Ralph, F.M.; Wick, G.A.; Lundquist, J.D.; Dettinger, M.D.

2008-01-01

The pre-cold-frontal low-level jet within oceanic extratropical cyclones represents the lower-tropospheric component of a deeper corridor of concentrated water vapor transport in the cyclone warm sector. These corridors are referred to as atmospheric rivers (ARs) because they are narrow relative to their length scale and are responsible for most of the poleward water vapor transport at midlatitudes. This paper investigates landfalling ARs along adjacent north- and south-coast regions of western North America. Special Sensor Microwave Imager (SSM/ I) satellite observations of long, narrow plumes of enhanced integrated water vapor (IWV) were used to detect ARs just offshore over the eastern Pacific from 1997 to 2005. The north coast experienced 301 AR days, while the south coast had only 115. Most ARs occurred during the warm season in the north and cool season in the south, despite the fact that the cool season is climatologically wettest for both regions. Composite SSM/I IWV analyses showed landfalling wintertime ARs extending northeastward from the tropical eastern Pacific, whereas the summertime composites were zonally oriented and, thus, did not originate from this region of the tropics. Companion SSM/I composites of daily rainfall showed significant orographic enhancement during the landfall of winter (but not summer) ARs. The NCEP-NCAR global reanalysis dataset and regional precipitation networks were used to assess composite synoptic characteristics and overland impacts of landfalling ARs. The ARs possess strong vertically integrated horizontal water vapor fluxes that, on average, impinge on the West Coast in the pre-cold-frontal environment in winter and post-cold-frontal environment in summer. Even though the IWV in the ARs is greater in summer, the vapor flux is stronger in winter due to much stronger flows associated with more intense storms. The landfall of ARs in winter and north-coast summer coincides with anomalous warmth, a trough offshore, and ridging over the Intermountain West, whereas the south-coast summer ARs coincide with relatively cold conditions and a near-coast trough. ARs have a much more profound impact on near-coast precipitation in winter than summer, because the terrain-normal vapor flux is stronger and the air more nearly saturated in winter. During winter, ARs produce roughly twice as much precipitation as all storms. In addition, wintertime ARs with the largest SSM/I IWV are tied to more intense storms with stronger flows and vapor fluxes, and more precipitation. ARs generally increase snow water equivalent (SWE) in autumn/winter and decrease SWE in spring. On average, wintertime SWE exhibits normal gains during north-coast AR storms and above-normal gains during the south-coast AR storms. The north-coast sites are mostly lower in altitude, where warmer-than-normal conditions more frequently yield rain. During those events when heavy rain from a warm AR storm falls on a preexisting snowpack, flooding is more likely to occur. ?? 2008 American Meteorological Society.

Ice conditions on the Chesapeake Bay as observed from LANDSAT during the winters of 1977, 1978 and 1979

NASA Technical Reports Server (NTRS)

Foster, J. L.

1980-01-01

The LANDSAT observations during the winters of 1977, 1978 and 1979, which were unusually cold in the northeastern U.S. and in the Chesapeake Bay area, were evaluated. Abnormal atmospheric circulation patterns displaced cold polar air to the south, and as a result, the Chesapeake Bay experienced much greater than normal icing conditions during these 3 years. The LANDSAT observations of the Chesapeake Bay area during these winters demonstrate the satellite's capabilities to monitor ice growth and melt, to detect ice motions, and to measure ice extent.

The experience of potentially vulnerable people during cold weather: implications for policy and practice.

PubMed

Jones, Lorelei; Mays, Nicholas

2016-08-01

To examine the experience of potentially vulnerable people during cold weather to inform interventions aimed at improving well-being. Qualitative study. Telephone interviews with 35 individuals who could be considered to be potentially vulnerable during cold weather. Individuals were interviewed on two occasions during the winter of 2012-13, one or two days after a level 3 cold weather alert, as defined by the Cold Weather Plan for England, had been issued. Participants were largely unaware of the health risks associated with low temperatures, especially cardiovascular risk. There was a clear distinction between the thermal experience of people in social housing, which was newer, had efficient heating, was well insulated and well-maintained, and owner occupiers living in older, harder to heat homes. Most participants relied on public transport, and many faced arduous journeys to reach basic facilities. Vulnerability to cold was mediated to a significant extent by practical social support from family members. Resources should be targeted at people in hard to heat homes and those that are socially isolated. The repertoire of initiatives aimed at reducing cold-related mortality and morbidity could usefully be augmented by efforts to reduce social isolation and build community resilience. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Effects of the large-scale atmospheric circulation on the onset and strength of urban heat islands: a case study

NASA Astrophysics Data System (ADS)

Targino, Admir Créso; Krecl, Patricia; Coraiola, Guilherme Conor

2014-07-01

Air temperature was monitored at 13 sites across the urban perimeter of a Brazilian midsize city in winter 2011. In this study, we show that the urban heat island (UHI) develops only at night and under certain weather conditions, and its intensity depends not only on the site's land cover but also on the meteorological setting. The urban heat island intensity was largest (6.6 °C) under lingering high-pressure conditions, milder (3.0 °C) under cold anticyclones and almost vanished (1.0 °C) during the passage of cold fronts. The cooling rates were calculated to monitor the growth and decay of the UHI over each specific synoptic setting. Over four contiguous days under the effect of a lingering high-pressure event, we observed that the onset of cooling was always at about 2 h before sunset. The reference site attained mean cooling rate of -2.6 °C h-1 at sunset, whilst the maximum urban rate was -1.2 °C h-1. Under a 3-day cold anticyclone episode, cooling also started about 2 h before sunset, and the difference between maximum rural (-2.0 °C h-1) and urban (-1.0 °C h-1) cooling rates diminished. Under cold-front conditions, the cooling rate was homogeneous for all sites and swang about zero throughout the day. The air temperature has a memory effect under lingering high-pressure conditions which intensified the UHI, in addition to the larger heat storage in the urban area. Cold anticyclone conditions promoted the development of the UHI; however, the cold air pool and relatively light winds smoothed out its intensity. Under the influence of cold fronts, the urban fabric had little effect on the city's air temperature field, and the UHI was imperceptible.

Impact of winter cooling on the northern part of the Black Sea.

NASA Astrophysics Data System (ADS)

Savchenko, Anatolii

2016-07-01

Climate change in the future may have a negative impact on many countries due to the increasing surface temperature and sea level rise. Probably, unprecedented largest positive trend of surface temperature, which observed since the mid XX century, has associated with increasing human activities around the world. Moreover, this warming will continue in this century, and at the end of the XXI century will be 2 - 5 ºC. Thus, investigation and monitoring of current climate are very important and necessary tasks. Regional model data (downscaling) and satellite data are used, because of underdeveloped network of meteorological stations in the northern part of the Black Sea region. Experiment of downscaling was carried out for the Black Sea region with a high spatial resolution of 0.22° x 0.22° for 1958 - 2007(daily values). For the Black Sea were also used satellite data of sea surface temperature(SST) from MyOcean-2 Project, which CNR(Rome) has reprocessed Pathfinder V5.2 (PFV52) AVHRR data over period 1981 - 2012 with daily gap-free maps (L4) at the original PFV52 resolution at 0.04° x 0.04°. Correlation between satellite SST and surface temperature from regional model climate are amounted 0,99. Thus, surface temperature of model and satellite data for the Black Sea is much correlated between yourself. The following integral characteristics of the Black Sea are referred to the area of sea limited by the 44 - 47º N and 28 - 34º E. Maximum cooling of the north-western part of the Black Sea in winter is occurs after invasion of cold air across the northern border of the basin. In addition, this water area is also interesting in the presence of her huge oil and gas reserves, as well as the construction of liquefied gas (crude oil) terminals. The maximum values of total heat flux (sensible + latent heat fluxes= Q) corresponding to the minimum values of SST are observed during the periods of the negative phase of the NAO. Besides, fluxes with extreme days P (Q) = 95% (the number of which is 5% of the total number of winter days) contribute ≈ 16 - 18% of the total heat flux during the winter, and with P (Q) = 90% - approximately 30%. Typical synoptic situation of extreme winter cooling P (Q) = 95% is presence of anticyclone in the district of Carpathian Mountains. North-easterly flow of cold air at high velocities near-surface wind leads to extreme total heat flux and decreasing SST. Satellite images of clouds well illustrate such cases as, for example, cold air invasion to the Black Sea area on January 23, 2006 (Satellite TERRA). Because of increase of risk associated with climate change, this topic is particularly relevant for the marine area, which is subjected to strong weathering during extreme events in winter. The monitoring of this area will allow reducing the damage from extreme natural events in the future.

40 CFR 86.213-11 - Fuel specifications.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.213-11 Fuel specifications. (a) Gasoline... the text in this section follows: Table—Cold CO Fuel Specifications Item ASTM test Cold CO low octane.... Diesel test fuel used for cold temperature FTP testing under part 600 of this chapter must be a winter...

40 CFR 86.213-11 - Fuel specifications.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.213-11 Fuel specifications. (a) Gasoline... the text in this section follows: Table—Cold CO Fuel Specifications Item ASTM test Cold CO low octane.... Diesel test fuel used for cold temperature FTP testing under part 600 of this chapter must be a winter...

40 CFR 86.213-11 - Fuel specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.213-11 Fuel specifications. (a) Gasoline... the text in this section follows: Table—Cold CO Fuel Specifications Item ASTM test Cold CO low octane.... Diesel test fuel used for cold temperature FTP testing under part 600 of this chapter must be a winter...

40 CFR 86.213-11 - Fuel specifications.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.213-11 Fuel specifications. (a) Gasoline... the text in this section follows: Table—Cold CO Fuel Specifications Item ASTM test Cold CO low octane.... Diesel test fuel used for cold temperature FTP testing under part 600 of this chapter must be a winter...

From genotype to phenotype: unraveling the complexities of cold adaptation in forest trees

Treesearch

Glenn T. Howe; Sally N. Aitken; David B. Neale; Kathleen D. Jermstad; Nicholas C. Wheeler; Tony H.H Chen

2003-01-01

Adaptation to winter cold in temperate and boreal trees involves complex genetic, physiological, and developmental processes. Genecological studies demonstrate the existence of steep genetic clines for cold adaptation traits in relation to environmental (mostly temperature related) gradients. Population differentiation is generally stronger for cold adaptation traits...

Monitoring responses to variation in food supply for a migratory waterfowl: American Black Duck (Anas rubripes) in winter.

PubMed

Barboza, Perry S; Jorde, Dennis G

2018-05-26

Wintering Black Ducks (Anas rubripes) concentrate in wetlands along the Atlantic coast where natural and anthropogenic disturbances have increased over the last 50 years, a period in which the population of Black Ducks has declined. We studied the sensitivity of Black Ducks to perturbations in food supply that often result from disturbances by storms, predators, and people. In the paper, we characterize the responses of captive Black Ducks to shifts in food quality and availability during winter and apply those measures to a comparison of wild birds. Captive ducks that were fed intermittently (3 consecutive days/week) compensated for fasted days to achieve similar body mass and body fat to control birds that were fed every day on both animal- and plant-based diets. However, birds that were fed intermittently expended 15% more energy each day than controls when both groups were fed (536 vs. 464 kJ/kg 0.75 ), which indicates that variable food supply increases the costs of maintenance and thus reduces the number of birds that can be supported on the same resource of food without interruptions to foraging. Egg production was not affected by diet quality provided in spring or by the frequency of feeding during the preceding winter months. Black Ducks lost body fat through winter in captivity and in the wild. Fat stores of birds in New Jersey were greater than those of birds in Maine (13.3 vs. 8.3% of body mass) in January, which reflected the high energy demands of cold temperatures in Maine. Values for ∂ 15 N were greater in Maine than in New Jersey for both red blood cells and plasma, which indicated a consistent diet of marine invertebrates in Maine. Greater isotopic variation in red blood cells indicated that diets were more diverse in New Jersey than in Maine for both ∂ 15 N (9.7 ± 1.1 vs. 11.2 ± 0.4‰) and for ∂ 13 C (- 15.1 ± 2.2 vs. - 13.8 ± 1.4‰). Plasma ∂ 13 C was enriched over red blood cells in wild birds especially those with low fat stores, which suggested birds with low energy stores were shifting diets. Black Ducks can compensate for disturbances in feeding by increasing intakes if they have access to high quality wetlands where they are able to find abundant food. High energy demands at cold temperatures may constrain fat stores and thus the tolerance of feeding disturbances especially at the northern limits of the winter range. We hypothesize that decreasing variation in diet may indicate an increase in vulnerability to disturbance in winter when body fat is low. Recent efforts to assess and improve habitat quality of Black Ducks could be enhanced by monitoring the body composition and diet of birds to assess their vulnerability to disturbances in food supply and energy demands.

Cold-Weather Sports

MedlinePlus

... Videos for Educators Search English Español Cold-Weather Sports KidsHealth / For Teens / Cold-Weather Sports What's in this article? What to Do? Classes ... weather. What better time to be outdoors? Winter sports can help you burn calories, increase your cardiovascular ...

More Frequent Weak Stratospheric Polar Vortex States Linked to Cold Extremes

NASA Astrophysics Data System (ADS)

Kretschmer, M.; Coumou, D.; Agel, L. A.; Barlow, M. A.; Tziperman, E.; Cohen, J. L.

2016-12-01

The extra-tropical stratosphere in boreal winter is characterized by a strong circumpolar westerly jet, referred to as the stratospheric polar vortex (SPV) which confines cold temperatures at high latitudes. Previous studies showed that a weak SPV can lead to cold-air outbreaks in the mid-latitudes but the exact relationships and mechanisms are still unclear. Particularly, it is unclear whether stratospheric variability has contributed to the observed anomalous cooling trends in Central and eastern Asia. Using hierarchical clustering, we show that over the last 37 years, the frequency of weak vortex states in mid to late winter (January and February) has increased significantly accompanied by subsequent cold surface temperatures in the mid-latitudes. Furthermore, we show that stratospheric and El Niño/Southern Oscillation (ENSO) variability can explain most of the observed spatially heterogenic winter temperature trends in the era of Arctic amplification but the contribution of ENSO is less important. We show that the weakening of the SPV was related to a strengthening Siberian high and poleward heat flux. These findings support the hypothesis that a warming Arctic has weakened the SPV and thereby increased the frequency of cold-air outbreaks.

Phthalate Esters in Indoor Window Films in a Northeastern Chinese Urban Center: Film Growth and Implications for Human Exposure.

PubMed

Huo, Chun-Yan; Liu, Li-Yan; Zhang, Zi-Feng; Ma, Wan-Li; Song, Wei-Wei; Li, Hai-Ling; Li, Wen-Long; Kannan, Kurunthachalam; Wu, Yong-Kai; Han, Ya-Meng; Peng, Zhi-Xiang; Li, Yi-Fan

2016-07-19

Indoor window film samples were collected in buildings during 2014-2015 for the determination of six phthalate diesters (PAEs). Linear regression analysis suggested that the film mass was positively and significantly correlated with the duration of film growth (from 7 to 77 days). PAEs were detected in all window film samples (n = 64). For all the samples with growth days ranged from 7 to 77 days, the median concentrations of total six PAEs (∑6PAEs) in winter and summer window film samples were 9900 ng/m(2) film (2000 μg/g film) and 4700 ng/m(2) film (650 μg/g film), respectively. Among PAEs analyzed, di-2-ethyl-hexyl phthalate (DEHP) was the major compound (71 ± 9.7%), followed by di-n-butyl phthalate (DBP; 20 ± 7.4%) and diisobutyl phthalate (DiBP; 5.1 ± 2.2%). Positive correlations among PAEs suggested their common sources in the window film samples. Room temperature and relative humidity were negatively and significantly correlated with PAEs concentations (in ng/m(2)). Poor ventilation in cold winter in Noreastern China significantly influenced the concentrations of PAEs in window film which suggested higher inhalation exposure dose in winter. The median hazard quotient (HQ) values from PAEs exposure were below 1, suggesting that the intake of PAEs via three exposure pathways was considered as acceptable.

Physiological ecology of overwintering in the hatchling painted turtle: multiple-scale variation in response to environmental stress.

PubMed

Costanzo, Jon P; Dinkelacker, Stephen A; Iverson, John B; Lee, Richard E

2004-01-01

We integrated field and laboratory studies in an investigation of water balance, energy use, and mechanisms of cold-hardiness in hatchling painted turtles (Chrysemys picta) indigenous to west-central Nebraska (Chrysemys picta bellii) and northern Indiana (Chrysemys picta marginata) during the winters of 1999-2000 and 2000-2001. We examined 184 nests, 80 of which provided the hatchlings (n=580) and/or samples of soil used in laboratory analyses. Whereas winter 1999-2000 was relatively dry and mild, the following winter was wet and cold; serendipitously, the contrast illuminated a marked plasticity in physiological response to environmental stress. Physiological and cold-hardiness responses of turtles also varied between study locales, largely owing to differences in precipitation and edaphics and the lower prevailing and minimum nest temperatures (to -13.2 degrees C) encountered by Nebraska turtles. In Nebraska, winter mortality occurred within 12.5% (1999-2000) and 42.3% (2000-2001) of the sampled nests; no turtles died in the Indiana nests. Laboratory studies of the mechanisms of cold-hardiness used by hatchling C. picta showed that resistance to inoculative freezing and capacity for freeze tolerance increased as winter approached. However, the level of inoculation resistance strongly depended on the physical characteristics of nest soil, as well as its moisture content, which varied seasonally. Risk of inoculative freezing (and mortality) was greatest in midwinter when nest temperatures were lowest and soil moisture and activity of constituent organic ice nuclei were highest. Water balance in overwintering hatchlings was closely linked to dynamics of precipitation and soil moisture, whereas energy use and the size of the energy reserve available to hatchlings in spring depended on the winter thermal regime. Acute chilling resulted in hyperglycemia and hyperlactemia, which persisted throughout winter; this response may be cryoprotective. Some physiological characteristics and cold-hardiness attributes varied between years, between study sites, among nests at the same site, and among siblings sharing nests. Such variation may reflect adaptive phenotypic plasticity, maternal or paternal influence on an individual's response to environmental challenge, or a combination of these factors. Some evidence suggests that life-history traits, such as clutch size and body size, have been shaped by constraints imposed by the harsh winter environment.

A chrysophyte-based quantitative reconstruction of winter severity from varved lake sediments in NE Poland during the past millennium and its relationship to natural climate variability

NASA Astrophysics Data System (ADS)

Hernández-Almeida, I.; Grosjean, M.; Przybylak, R.; Tylmann, W.

2015-08-01

Chrysophyte cysts are recognized as powerful proxies of cold-season temperatures. In this paper we use the relationship between chrysophyte assemblages and the number of days below 4 °C (DB4 °C) in the epilimnion of a lake in northern Poland to develop a transfer function and to reconstruct winter severity in Poland for the last millennium. DB4 °C is a climate variable related to the length of the winter. Multivariate ordination techniques were used to study the distribution of chrysophytes from sediment traps of 37 low-land lakes distributed along a variety of environmental and climatic gradients in northern Poland. Of all the environmental variables measured, stepwise variable selection and individual Redundancy analyses (RDA) identified DB4 °C as the most important variable for chrysophytes, explaining a portion of variance independent of variables related to water chemistry (conductivity, chlorides, K, sulfates), which were also important. A quantitative transfer function was created to estimate DB4 °C from sedimentary assemblages using partial least square regression (PLS). The two-component model (PLS-2) had a coefficient of determination of Rcross2 = 0.58, with root mean squared error of prediction (RMSEP, based on leave-one-out) of 3.41 days. The resulting transfer function was applied to an annually-varved sediment core from Lake Żabińskie, providing a new sub-decadal quantitative reconstruction of DB4 °C with high chronological accuracy for the period AD 1000-2010. During Medieval Times (AD 1180-1440) winters were generally shorter (warmer) except for a decade with very long and severe winters around AD 1260-1270 (following the AD 1258 volcanic eruption). The 16th and 17th centuries and the beginning of the 19th century experienced very long severe winters. Comparison with other European cold-season reconstructions and atmospheric indices for this region indicates that large parts of the winter variability (reconstructed DB4 °C) is due to the interplay between the oscillations of the zonal flow controlled by the North Atlantic Oscillation (NAO) and the influence of continental anticyclonic systems (Siberian High, East Atlantic/Western Russia pattern). Differences with other European records are attributed to geographic climatological differences between Poland and Western Europe (Low Countries, Alps). Striking correspondence between the combined volcanic and solar forcing and the DB4 °C reconstruction prior to the 20th century suggests that winter climate in Poland responds mostly to natural forced variability (volcanic and solar) and the influence of unforced variability is low.

Winter cold-tolerance thresholds in field-grown Miscanthus hybrid rhizomes.

PubMed

Peixoto, Murilo de Melo; Friesen, Patrick Calvin; Sage, Rowan F

2015-07-01

The cold tolerance of winter-dormant rhizomes was evaluated in diploid, allotriploid, and allotetraploid hybrids of Miscanthus sinensis and Miscanthus sacchariflorus grown in a field setting. Two artificial freezing protocols were tested: one lowered the temperature continuously by 1°C h(-1) to the treatment temperature and another lowered the temperature in stages of 24h each to the treatment temperature. Electrolyte leakage and rhizome sprouting assays after the cold treatment assessed plant and tissue viability. Results from the continuous-cooling trial showed that Miscanthus rhizomes from all genotypes tolerated temperatures as low as -6.5 °C; however, the slower, staged-cooling procedure enabled rhizomes from two diploid lines to survive temperatures as low as -14 °C. Allopolyploid genotypes showed no change in the lethal temperature threshold between the continuous and staged-cooling procedure, indicating that they have little ability to acclimate to subzero temperatures. The results demonstrated that rhizomes from diploid Miscanthus lines have superior cold tolerance that could be exploited to improve performance in more productive polyploid lines. With expected levels of soil insulation, low winter air temperatures should not harm rhizomes of tolerant diploid genotypes of Miscanthus in temperate to sub-boreal climates (up to 60°N); however, the observed winter cold in sub-boreal climates could harm rhizomes of existing polyploid varieties of Miscanthus and thus reduce stand performance. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Calcium addition at the Hubbard Brook Experimental Forest increases sugar storage, antioxidant activity and cold tolerance in native red spruce (Picea rubens).

PubMed

Halman, Joshua M; Schaberg, Paul G; Hawley, Gary J; Eagar, Christopher

2008-06-01

In fall (November 2005) and winter (February 2006), we collected current-year foliage of native red spruce (Picea rubens Sarg.) growing in a reference watershed and in a watershed treated in 1999 with wollastonite (CaSiO(3), a slow-release calcium source) to simulate preindustrial soil calcium concentrations (Ca-addition watershed) at the Hubbard Brook Experimental Forest (Thornton, NH). We analyzed nutrition, soluble sugar concentrations, ascorbate peroxidase (APX) activity and cold tolerance, to evaluate the basis of recent (2003) differences between watersheds in red spruce foliar winter injury. Foliar Ca and total sugar concentrations were significantly higher in trees in the Ca-addition watershed than in trees in the reference watershed during both fall (P=0.037 and 0.035, respectively) and winter (P=0.055 and 0.036, respectively). The Ca-addition treatment significantly increased foliar fructose and glucose concentrations in November (P=0.013 and 0.007, respectively) and foliar sucrose concentrations in winter (P=0.040). Foliar APX activity was similar in trees in both watersheds during fall (P=0.28), but higher in trees in the Ca-addition watershed during winter (P=0.063). Cold tolerance of foliage was significantly greater in trees in the Ca-addition watershed than in trees in the reference watershed (P<0.001). Our results suggest that low foliar sugar concentrations and APX activity, and reduced cold tolerance in trees in the reference watershed contributed to their high vulnerability to winter injury in 2003. Because the reference watershed reflects forest conditions in the region, the consequences of impaired physiological function caused by soil Ca depletion may have widespread implications for forest health.

Could behaviour and not physiological thermal tolerance determine winter survival of aphids in cereal fields?

PubMed

Alford, Lucy; Andrade, Thiago Oliveira; Georges, Romain; Burel, Françoise; van Baaren, Joan

2014-01-01

Traits of physiological thermotolerance are commonly measured in the laboratory as predictors of the field success of ectotherms at unfavourable temperatures (e.g. during harsh winters, heatwaves, or under conditions of predicted global warming). Due to being more complicated to measure, behavioural thermoregulation is less commonly studied, although both physiology and behaviour interact to explain the survival of ectotherms. The aphids Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae are commercially important pests of temperate cereal crops. Although coexisting, these species markedly differ in winter success, with R. padi being the most abundant species during cold winters, followed by S. avenae and lastly M. dirhodum. To better understand the thermal physiology and behavioural factors contributing to differential winter success, the lethal temperature (physiological thermotolerance) and the behaviour of aphids in a declining temperature regime (behavioural thermotolerance) of these three species were investigated. Physiological thermotolerance significantly differed between the three species, with R. padi consistently the least cold tolerant and S. avenae the most cold tolerant. However, although the least cold tolerant of the study species, significantly more R. padi remained attached to the host plant at extreme sub-zero temperatures than S. avenae and M. dirhodum. Given the success of anholocyclic R. padi in harsh winters compared to its anholocyclic counterparts, this study illustrates that behavioural differences could be more important than physiological thermotolerance in explaining resistance to extreme temperatures. Furthermore it highlights that there is a danger to studying physiological thermotolerance in isolation when ascertaining risks of ectotherm invasions, the establishment potential of exotic species in glasshouses, or predicting species impacts under climate change scenarios.

Link between the Barents Oscillation and recent boreal winter cooling over the Asian midlatitudes

NASA Astrophysics Data System (ADS)

Shu, Qi; Qiao, Fangli; Song, Zhenya; Song, Yajuan

2018-01-01

The link between boreal winter cooling over the midlatitudes of Asia and the Barents Oscillation (BO) since the late 1980s is discussed in this study, based on five datasets. Results indicate that there is a large-scale boreal winter cooling during 1990-2015 over the Asian midlatitudes, and that it is a part of the decadal oscillations of long-term surface air temperature (SAT) anomalies. The SAT anomalies over the Asian midlatitudes are significantly correlated with the BO in boreal winter. When the BO is in its positive phase, anomalously high sea level pressure over the Barents region, with a clockwise wind anomaly, causes cold air from the high latitudes to move over the midlatitudes of Asia, resulting in anomalous cold conditions in that region. Therefore, the recent increasing trend of the BO has contributed to recent winter cooling over the Asian midlatitudes.

Recent advances in sustainable winter road operations – a book proposal.

DOT National Transportation Integrated Search

2017-05-05

Investing in winter transportation operations is essential and beneficial to the public and the economy. The U.S. economy cannot afford the cost of shutting down highways, airports, etc., during winter weather. In the northern U.S. and other cold-cli...

Seedling phenology and cold hardiness: Moving targets

Treesearch

Diane L. Haase

2011-01-01

Phenology is the annual cycle of plant development as influenced by seasonal variations. Dormancy and cold hardiness are two aspects of the annual cycle. In temperate plants, the development of cold hardiness results in the ability to withstand subfreezing winter temperatures. Cold hardiness is also a reflection of overall stress resistance. In addition to describing...

Role of photoperiod and melatonin in seasonal acclimatization of the djungarian hamster, Phodopus sungorus

NASA Astrophysics Data System (ADS)

Steinlechner, S.; Heldmaier, G.

1982-12-01

The Djungarian hamster, Phodopus sungorus, shows a clear annual cycle in some thermogenic parameters such as nonshivering thermogenesis (NST) and cold resistance. These seasonal changes were found to be basically controlled by natural changes in photoperiod. Further support for this view was obtained by exposing the hamsters to artificial long and short photoperiods. Implantation of melatonin during fall and winter results in an increased thermogenic capacity in both short and long day hamsters comparable to that shown by values of control hamsters exposed to short photoperiods during winter. This thermotropic action of melatonin and of short photoperiod could be found only in fall and winter whereas during spring and summer, melatonin, like photoperiod, had no influence on thermogenic capacities. These results show that the actions of melatonin and photoperiod vary with the season and that they depend upon the photoperiodic history of the hamsters. Our results further indicate that the pineal gland with its hormone melatonin is involved in mediation of photoperiodic control of seasonal acclimatization.

Winter cold of eastern continental boundaries induced by warm ocean waters.

PubMed

Kaspi, Yohai; Schneider, Tapio

2011-03-31

In winter, northeastern North America and northeastern Asia are both colder than other regions at similar latitudes. This has been attributed to the effects of stationary weather systems set by elevated terrain (orography), and to a lack of maritime influences from the prevailing westerly winds. However, the differences in extent and orography between the two continents suggest that further mechanisms are involved. Here we show that this anomalous winter cold can result in part from westward radiation of large-scale atmospheric waves--nearly stationary Rossby waves--generated by heating of the atmosphere over warm ocean waters. We demonstrate this mechanism using simulations with an idealized general circulation model, with which we show that the extent of the cold region is controlled by properties of Rossby waves, such as their group velocity and its dependence on the planetary rotation rate. Our results show that warm ocean waters contribute to the contrast in mid-latitude winter temperatures between eastern and western continental boundaries not only by warming western boundaries, but also by cooling eastern boundaries.

Distribution and diurnal behavior of Steller's Eiders wintering on the Alaska Peninsula

USGS Publications Warehouse

Laubhan, M.K.; Metzner, K.A.

1999-01-01

We studied the distribution and activities of adult Steller's Eiders (Polysticta stelleri) during winter and spring on a deep-water embayment and a shallow lagoon along the Alaska Peninsula from September 1980 to May 1981. During the remigial molt, eiders were observed on Izembek Lagoon but not on Cold Bay. Following the flightless period, Izembek Lagoon continued to support 63-100% of eiders encountered during surveys. As ice cover on Izembek Lagoon increased, the number of birds decreased on Izembek Lagoon but increased on Cold Bay, suggesting that some eiders disperse to nearshore, deep-water habitats in close proximity to Izembek Lagoon during severe weather. Diurnal activity budgets indicated that the amount of time resting or engaged in aggression and alert activities was similar among locations, seasons, tidal stages, and sexes. In contrast, time spent foraging differed among seasons and locations but did not differ among tidal stages or sexes. Although time spent foraging was similar during winter and spring on Izembek Lagoon, eiders on Cold Bay foraged more during winter compared to spring. Synchronous diving was the dominant foraging strategy.

Identifying environmental features for land management decisions

NASA Technical Reports Server (NTRS)

1983-01-01

Pairs of HCMM day-night thermal infrared (IR) data were selected to examine patterns of surface temperature and thermal inertia (TI) of peninsular Florida. GOES and NOAA-6 thermal IR, as well as National Climatic Center temperatures and rainfall, were also used. The HCMM apparent thermal inertia (ATI) images closely correspond to the General Soil Map of Florida, based on soil drainage classes. Areas with low ATI overlay well-drained soils, such as deep sands and drained organic soils. Areas with high ATI overlay areas with wetlands and bodies of water. The HCMM ATI images also correspond well with GOES-detected winter nocturnal cold-prone areas. Use of HCMM data with Carlson's energy balance model shows both high moisture availability (MA) and high thermal inertia (TI) of wetland-type surfaces and low MA and low TI of upland, well-drained soils. Since soil areas with low TI develop higher temperatures during the day, then antecedent patterns of highest maximum daytime surface temperature can also be used to predict nocturnal cold-prone areas in Florida.

Lake Stability and Winter-Spring Transitions: Decoupled Ice Duration and Winter Stratification

NASA Astrophysics Data System (ADS)

Daly, J.; Dana, S.; Neal, B.

2016-12-01

Ice-out is an important historical record demonstrating the impact of warmer air temperatures on lake ice. To better understand regional differences in ice-out trends, to characterize the thermal dynamics of smaller mountain lakes, and to develop baseline data for Maine's high elevations landscapes, sub-hourly water temperatures have been collected in over a dozen of Maine's mountain lakes since 2010. Both surface water and hypolimnion temperature data are recorded year-round, facilitating the determination of ice-in, ice-out, and the duration of winter stratification. The multi-year record from sites across as 250 km transect allows us to compare spatial variability related to lake morphometry and location with inter-annual variability related to local weather. All of the study lakes are large enough to stratify during the summer and mix extensively during the fall. Most years, our data show that the onset of winter stratification is nearly synchronous across the study area and is associated with cold air temperatures. Winter stratification can begin days to weeks before ice-in; the timing of ice-in shows more variability, with both elevation and basin aspect influencing the timing. Ice-out shows both the anticipated spatial and interannual variability; some years there is strong coherence between locations while other years show high variability, possibly a function of differences in snowpack. Ice-out is not always immediately followed by the end of winter stratification, there is sometimes a lag of days to weeks before the lakes mix. If the warm temperatures that lead to ice-out are followed by calm days without significant wind, the surface of some lakes begins to warm quickly maintaining the density difference and prolonging winter stratification. The longer the lag time, the stronger the density difference becomes which may also result in a very brief period of mixing in the spring prior to set-up of summer stratification. This year's El Niño event resulted in very late ice-in, leading to an unusually short ice duration period at most sites. However, ice-out for these sites was within the range observed previous years and there may not be a significant impact on summer water temperatures.

Atlantic Meridional Overturning Circulation slowdown cooled the subtropical ocean

PubMed Central

Cunningham, Stuart A; Roberts, Christopher D; Frajka-Williams, Eleanor; Johns, William E; Hobbs, Will; Palmer, Matthew D; Rayner, Darren; Smeed, David A; McCarthy, Gerard

2013-01-01

[1] Observations show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that these cold anomalies are partly driven by anomalous air-sea exchange during the cold winters of 2009/2010 and 2010/2011 and, more surprisingly, by extreme interannual variability in the ocean's northward heat transport at 26.5°N. This cooling driven by the ocean's meridional heat transport affects deeper layers isolated from the atmosphere on annual timescales and water that is entrained into the winter mixed layer thus lowering winter sea surface temperatures. Here we connect, for the first time, variability in the northward heat transport carried by the Atlantic Meridional Overturning Circulation to widespread sustained cooling of the subtropical North Atlantic, challenging the prevailing view that the ocean plays a passive role in the coupled ocean-atmosphere system on monthly-to-seasonal timescales. PMID:26074634

Atlantic Meridional Overturning Circulation slowdown cooled the subtropical ocean.

PubMed

Cunningham, Stuart A; Roberts, Christopher D; Frajka-Williams, Eleanor; Johns, William E; Hobbs, Will; Palmer, Matthew D; Rayner, Darren; Smeed, David A; McCarthy, Gerard

2013-12-16

[1] Observations show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that these cold anomalies are partly driven by anomalous air-sea exchange during the cold winters of 2009/2010 and 2010/2011 and, more surprisingly, by extreme interannual variability in the ocean's northward heat transport at 26.5°N. This cooling driven by the ocean's meridional heat transport affects deeper layers isolated from the atmosphere on annual timescales and water that is entrained into the winter mixed layer thus lowering winter sea surface temperatures. Here we connect, for the first time, variability in the northward heat transport carried by the Atlantic Meridional Overturning Circulation to widespread sustained cooling of the subtropical North Atlantic, challenging the prevailing view that the ocean plays a passive role in the coupled ocean-atmosphere system on monthly-to-seasonal timescales.

COLD HARDINESS AND RANGE OF THE MYRIAPOD Angarozonium amurense (POLYZONIIDAE, DIPLOPODA, ARTHROPODA) IN PERMAFROST ENVIRONMENTS.

PubMed

Berman, D I; Meshcheryakova, E N; Mikhaljova, E V

2015-01-01

Angarozonium amurense (Gerstfeldt, 1859) is the only one out of more than a hundred diplopod species described in Siberia and the Far East that inhabits regions with solid permafrost. To evaluate the cold hardiness of A. amurense that allows this species to inhabit permafrost regions. The survival temperature thresholds and supercooling points (SCP) were measured. The temperature thresholds for adult animal survival are -8.5 C in summer and -27 C in winter. Average SCP decreases from -7.7 in summer to -16.9 in winter. Water content decreases from 55.7% in summer to 49.4% in winter. The cold hardiness of A. amurense sets the record in this class of animals. It allows it to overwinter in the upper 15 centimeters layer of soil in most biotopes of the coldest permafrost regions in North Asia.

Simulation of a Severe Autumn/Winter Drought in Eastern China by Regional Atmospheric Modeling System(RAMS)

NASA Astrophysics Data System (ADS)

Meng, Chunchun; Ma, Yaoming

2016-04-01

Compared with European Centre for Medium-Range Weather Forecasts (ERA-interim) Reanalysis data and Global Summary Of Day (GSOD) observation data, the outcomes from RAMS of the 2008/2009 severe autumn/winter drought in eastern china are analyzed in this study. The reanalysis data showed that most parts of north China are controlled by northwest wind which was accompanied by cold air, the warm and moist air from South Sea is so weak to meet with cold air, therefore forming a circulation which is unfavorable for the formation of precipitation over Eastern China. RAMS performs very well over the simulation of this atmospheric circulation, so do the rainfall and air temperature over China and where the drought occurred. Meanwhile, the simulation of the time series of precipitation and temperature behaves excellent, the square of correlation coefficient between simulations and observations reached above 0.8. Although the performance of RAMS on this drought simulation is fairly accurate, there is amount of research work to be continued to complete a more realistic simulation. KEY WORDS RAMS; severe drought; numerical simulation; atmospheric circulation; precipitation and air temperature

Terral De Vicuna, a Foehnlike Wind in Semiarid Northern Chile: Meteorological Aspects and Implications for the Fulfillment of Chill Requirements in Deciduous Fruit Trees

NASA Technical Reports Server (NTRS)

Montes, Carlo; Rutllant, Jose A.; Aguirre, Anita; Bascunan-Godoy, Luisa; Julia, Cristobal

2016-01-01

The terral de Vicuña is a warm and dry wind that flows down the Elqui Valley in north-central Chile typically at dawn and early morning. Given that most terral episodes occur in austral winter when chill accumulation by deciduous fruit trees proceeds, negative effects on agriculture may be expected. During 11 (2004-14) winters a meteorological characterization of terral winds and the assessment of their impact on chill accumulation, by the modified Utah Model and the Dynamic Model, were performed. Within this period, 67 terral days (TD) were identified as those in which nighttime to early morning wind direction and speed, air temperature, and relative humidity reached defined thresholds on an hourly basis (terral hours). Most frequent TD featured 6-9 consecutive terral hours; duration is considered here as a proxy for their intensity. Synoptic-scale meteorological analysis shows that 65% of moderate and strong terral events develop as a cold, migratory anticyclone drifts poleward of the study area, coinciding with the onset of a midtropospheric ridge over central Chile, bringing southwest winds on top of the Andes (approximately 500-hPa level). The remaining 35% are either associated with 500-hPa easterlies (foehn like), with prefrontal conditions ahead of a trough driving northwest 500-hPa winds, or with transitional 500-hPa westerlies.Assessments of chill accumulation during TD show that, although present average and cold winter conditions do not represent a major TD hazard to local agriculture, lower chill accumulation associated with anomalously high nocturnal temperatures could be significantly more important during present and future warmer winters.

Factors affecting outdoor exposure in winter: population-based study

NASA Astrophysics Data System (ADS)

Mäkinen, Tiina M.; Raatikka, Veli-Pekka; Rytkönen, Mika; Jokelainen, Jari; Rintamäki, Hannu; Ruuhela, Reija; Näyhä, Simo; Hassi, Juhani

2006-09-01

The extent of outdoor exposure during winter and factors affecting it were examined in a cross-sectional population study in Finland. Men and women aged 25-74 years from the National FINRISK 2002 sub-study ( n=6,591) were queried about their average weekly occupational, leisure-time and total cold exposure during the past winter. The effects of gender, age, area of residence, occupation, ambient temperature, self-rated health, physical activity and education on cold exposure were analysed. The self-reported median total cold exposure time was 7 h/week (8 h men, 6 h women),<1 h/week (2 h men, 0 h women) at work, 4 h/week (5 h men, 4 h women) during leisure time and 1 h/week (1 h men, 1.5 h women) while commuting to work. Factors associated with increased occupational cold exposure among men were: being employed in agriculture, forestry and industry/mining/construction or related occupations, being less educated and being aged 55-64 years. Factors associated with increased leisure-time cold exposure among men were: employment in industry/mining/construction or related occupations, being a pensioner or unemployed, reporting at least average health, being physically active and having college or vocational education. Among women, being a housewife, pensioner or unemployed and engaged in physical activity increased leisure-time cold exposure, and young women were more exposed than older ones. Self-rated health was positively associated with leisure time cold exposure in men and only to a minor extent in women. In conclusion, the subjects reported spending 4% of their total time under cold exposure, most of it (71%) during leisure time. Both occupational and leisure-time cold exposure is greater among men than women.

Effect of the Winter Wheat Cheyenne 5A Substituted Chromosome on Dynamics of Abscisic Acid and Cytokinins in Freezing-Sensitive Chinese Spring Genetic Background

PubMed Central

Kalapos, Balázs; Novák, Aliz; Dobrev, Petre; Vítámvás, Pavel; Marincs, Ferenc; Galiba, Gábor; Vanková, Radomira

2017-01-01

The effect of short- and long-term cold treatment on the abscisic acid (ABA) and cytokinin (CK) metabolism, and their main biosynthesis- and signaling-related genes were investigated in freezing-sensitive and freezing-tolerant wheat genotypes. Varieties Cheyenne and Chinese Spring substituted with the 5A Cheyenne chromosome, which represented freezing-tolerant genotypes, were compared with the freezing-sensitive Chinese Spring. Hormone levels and gene expression data indicated that the short- and long-term cold treatments are associated with specific regulation of the accumulation of cold-protective proteins and phytohormone levels, as well as the expression profiles of the hormone-related genes. The significant differences were observed between the genotypes, and between their leaf and crown tissues, too. The level of dehydrins, including WCS120 protein, and expression of WCS120 gene were considerably higher in the freezing-tolerant genotypes after 21 days of cold treatment. Expression of Cor14b and CBF14, cold-responsive regulator genes, was increased by cold treatment in all genotypes, to higher extent in freezing-tolerant genotypes. Cluster analysis revealed that the tolerant genotypes had a similar response to cold treatment, regarding expression of the ABA and CK metabolic genes, as well as hormone levels in leaves. As far as hormone levels in crowns are concerned, however, the strongly freezing-tolerant Cheyenne variety clustered separately from the Chinese Spring and the substitution line, which were more similar to each other after both 1 and 21 days of cold treatment than to Cheyenne. Based on these results we concluded that the 5A chromosome of wheat might have both a direct and an indirect impact on the phytohormone-dependent cold-induced freezing tolerance. Based on the gene expression data, novel genetic markers could be developed, which may be used to determine the freezing tolerance level in a wide range of wheat varieties. PMID:29238355

The overwintering physiology of the emerald ash borer, Agrilus planipennis fairmaire (coleoptera: buprestidae).

PubMed

Crosthwaite, Jill C; Sobek, Stephanie; Lyons, D Barry; Bernards, Mark A; Sinclair, Brent J

2011-01-01

Ability to survive cold is an important factor in determining northern range limits of insects. The emerald ash borer (Agrilus planipennis) is an invasive beetle introduced from Asia that is causing extensive damage to ash trees in North America, but little is known about its cold tolerance. Herein, the cold tolerance strategy and mechanisms involved in the cold tolerance of the emerald ash borer were investigated, and seasonal changes in these mechanisms monitored. The majority of emerald ash borers survive winter as freeze-intolerant prepupae. In winter, A. planipennis prepupae have low supercooling points (approximately -30°C), which they achieve by accumulating high concentrations of glycerol (approximately 4M) in their body fluids and by the synthesis of antifreeze agents. Cuticular waxes reduce inoculation from external ice. This is the first comprehensive study of seasonal changes in cold tolerance in a buprestid beetle. 2010 Elsevier Ltd. All rights reserved.

Temperature Studies with the Asian Citrus Psyllid, Diaphorina citri: Cold Hardiness and Temperature Thresholds for Oviposition

PubMed Central

Hall, David G.; Wenninger, Erik J.; Hentz, Matthew G.

2011-01-01

This study was conducted to obtain information on the cold hardiness of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in Florida and to assess upper and lower temperature thresholds for oviposition. The psyllid is an important pest in citrus because it transmits the bacterial pathogens responsible for citrus greening disease, Huanglongbing, considered the most serious citrus disease worldwide. D. citri was first found in Florida during 1998, and the disease was discovered during 2005. Little was known regarding cold hardiness of D. citri, but Florida citrus is occasionally subjected to notable freeze events. Temperature and duration were each significant sources of variation in percent mortality of D. citri subjected to freeze events. Relatively large percentages of adults and nymphs survived after being exposed for several hours to temperatures as low as -5 to -6° C. Relatively large percentages of eggs hatched after being exposed for several hours to temperatures as low as -8° C. Research results indicated that adult D. citri become cold acclimated during the winter through exposure to cooler winter temperatures. There was no evidence that eggs became cold acclimated during winter. Cold acclimation in nymphs was not investigated. Research with adult D. citri from laboratory and greenhouse colonies revealed that mild to moderate freeze events were usually nonlethal to the D. citri irrespective of whether they were cold acclimated or not. Upper and lower temperature thresholds for oviposition were investigated because such information may be valuable in explaining the geographic distribution and potential spread of the pest from Florida as well as how cooler winter temperatures might limit population growth. The estimated lower and upper thresholds for oviposition were 16.0 and 41.6° C, respectively; the estimated temperature of peak oviposition over a 48 h period was 29.6° C. PMID:21870969

Temperature studies with the Asian citrus psyllid, Diaphorina citri: cold hardiness and temperature thresholds for oviposition.

PubMed

Hall, David G; Wenninger, Erik J; Hentz, Matthew G

2011-01-01

This study was conducted to obtain information on the cold hardiness of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in Florida and to assess upper and lower temperature thresholds for oviposition. The psyllid is an important pest in citrus because it transmits the bacterial pathogens responsible for citrus greening disease, Huanglongbing, considered the most serious citrus disease worldwide. D. citri was first found in Florida during 1998, and the disease was discovered during 2005. Little was known regarding cold hardiness of D. citri, but Florida citrus is occasionally subjected to notable freeze events. Temperature and duration were each significant sources of variation in percent mortality of D. citri subjected to freeze events. Relatively large percentages of adults and nymphs survived after being exposed for several hours to temperatures as low as -5 to -6 °C. Relatively large percentages of eggs hatched after being exposed for several hours to temperatures as low as -8 °C. Research results indicated that adult D. citri become cold acclimated during the winter through exposure to cooler winter temperatures. There was no evidence that eggs became cold acclimated during winter. Cold acclimation in nymphs was not investigated. Research with adult D. citri from laboratory and greenhouse colonies revealed that mild to moderate freeze events were usually nonlethal to the D. citri irrespective of whether they were cold acclimated or not. Upper and lower temperature thresholds for oviposition were investigated because such information may be valuable in explaining the geographic distribution and potential spread of the pest from Florida as well as how cooler winter temperatures might limit population growth. The estimated lower and upper thresholds for oviposition were 16.0 and 41.6 °C, respectively; the estimated temperature of peak oviposition over a 48 h period was 29.6 °C.

Coherent variability between seasonal temperatures and rainfalls in the Iberian Peninsula, 1951-2016

NASA Astrophysics Data System (ADS)

Rodrigo, F. S.

2018-02-01

In this work trends of seasonal mean of daily minimum (TN), maximum (TX), mean (TM) temperatures, daily range of temperature (DTR), and total seasonal rainfall (R) in 35 Iberian stations since mid-twentieth century are studied. The interest is focused on the relationships between temperature variables and rainfall, taking into account the correlation coefficients between R and the temperature variables. The negative link between rainfall and temperatures is detected in the four seasons of the year, except in western stations in winter for TN and TM, and in autumn for TN (for this variable a certain annual cycle is detected, with predominance of positive correlation in winter, negative in spring and summer, and the autumn as transition season). The role of cloud cover is confirmed in those stations with total cloud cover data. Using an average peninsular series, the relationship between nighttime temperature and rainfall related to long wave radiation is confirmed for the four seasons of the year, although in spring and summer has minor importance than in the cold half year. The relationships between R, TN, and TX are in general terms stable after a moving correlation analysis, although the negative correlation between TX and R seems be weakened in spring and autumn and reinforced in summer. The role of convective precipitation in autumn is discussed. The analysis of combined extreme indices in four representative stations shows an increase of warm and dry days, and a decrease of cold and wet days.

Temperature-Related Death and Illness. Chapter 2

NASA Technical Reports Server (NTRS)

Sarofim, Marcus C.; Saha, Shubhayu; Hawkins, Michelle D.; Mills, David M.; Hess, Jeremy; Horton, Radley; Kinney, Patrick; Schwartz, Joel; St. Juliana, Alexis

2016-01-01

Based on present-day sensitivity to heat, an increase of thousands to tens of thousands of premature heat-related deaths in the summer and a decrease of premature cold-related deaths in the winter are projected each year as a result of climate change by the end of the century. Future adaptation will very likely reduce these impacts (see Changing Tolerance to Extreme Heat Finding). The reduction in cold-related deaths is projected to be smaller than the increase in heat-related deaths in most regions. Days that are hotter than usual in the summer or colder than usual in the winter are both associated with increased illness and death. Mortality effects are observed even for small differences from seasonal average temperatures. Because small temperature differences occur much more frequently than large temperature differences, not accounting for the effect of these small differences would lead to underestimating the future impact of climate change. An increase in population tolerance to extreme heat has been observed over time. Changes in this tolerance have been associated with increased use of air conditioning, improved social responses, and or physiological acclimatization, among other factors. Expected future increases in this tolerance will reduce the projected increase in deaths from heat. Older adults and children have a higher risk of dying or becoming ill due to extreme heat. People working outdoors, the socially isolated and economically disadvantaged, those with chronic illnesses, as well as some communities of color, are also especially vulnerable to death or illness.

OeFAD8, OeLIP and OeOSM expression and activity in cold-acclimation of Olea europaea, a perennial dicot without winter-dormancy.

PubMed

D'Angeli, Simone; Matteucci, Maya; Fattorini, Laura; Gismondi, Angelo; Ludovici, Matteo; Canini, Antonella; Altamura, Maria Maddalena

2016-05-01

Cold-acclimation genes in woody dicots without winter-dormancy, e.g., olive-tree, need investigation. Positive relationships between OeFAD8, OeOSM , and OeLIP19 and olive-tree cold-acclimation exist, and couple with increased lipid unsaturation and cutinisation. Olive-tree is a woody species with no winter-dormancy and low frost-tolerance. However, cold-tolerant genotypes were empirically selected, highlighting that cold-acclimation might be acquired. Proteins needed for olive-tree cold-acclimation are unknown, even if roles for osmotin (OeOSM) as leaf cryoprotectant, and seed lipid-transfer protein for endosperm cutinisation under cold, were demonstrated. In other species, FAD8, coding a desaturase producing α-linolenic acid, is activated by temperature-lowering, concomitantly with bZIP-LIP19 genes. The research was focussed on finding OeLIP19 gene(s) in olive-tree genome, and analyze it/their expression, and that of OeFAD8 and OeOSM, in drupes and leaves under different cold-conditions/developmental stages/genotypes, in comparison with changes in unsaturated lipids and cell wall cutinisation. Cold-induced cytosolic calcium transients always occurred in leaves/drupes of some genotypes, e.g., Moraiolo, but ceased in others, e.g., Canino, at specific drupe stages/cold-treatments, suggesting cold-acclimation acquisition only in the latter genotypes. Canino and Moraiolo were selected for further analyses. Cold-acclimation in Canino was confirmed by an electrolyte leakage from leaf/drupe membranes highly reduced in comparison with Moraiolo. Strong increases in fruit-epicarp/leaf-epidermis cutinisation characterized cold-acclimated Canino, and positively coupled with OeOSM expression, and immunolocalization of the coded protein. OeFAD8 expression increased with cold-acclimation, as the production of α-linolenic acid, and related compounds. An OeLIP19 gene was isolated. Its levels changed with a trend similar to OeFAD8. All together, results sustain a positive relationship between OeFAD8, OeOSM and OeLIP19 expression in olive-tree cold-acclimation. The parallel changes in unsaturated lipids and cutinisation concur to suggest orchestrated roles of the coded proteins in the process.

Freeze-Testing in St. Augustinegrass II: Evaluation of acclimation effects

USDA-ARS?s Scientific Manuscript database

Winter survivability is a major-limiting factor for St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze) grown in the transition zone of the United States as cold winters can result in high levels of winterkill. In addition to field studies, lab-based freeze tests mimicking field winter survi...

Quantifying wintertime boundary layer ozone production from frequent profile measurements in the Uinta Basin, UT, oil and gas region

NASA Astrophysics Data System (ADS)

Schnell, Russell C.; Johnson, Bryan J.; Oltmans, Samuel J.; Cullis, Patrick; Sterling, Chance; Hall, Emrys; Jordan, Allen; Helmig, Detlev; Petron, Gabrielle; Ahmadov, Ravan; Wendell, James; Albee, Robert; Boylan, Patrick; Thompson, Chelsea R.; Evans, Jason; Hueber, Jacques; Curtis, Abigale J.; Park, Jeong-Hoo

2016-09-01

As part of the Uinta Basin Winter Ozone Study, January-February 2013, we conducted 937 tethered balloon-borne ozone vertical and temperature profiles from three sites in the Uinta Basin, Utah (UB). Emissions from oil and gas operations combined with snow cover were favorable for producing high ozone-mixing ratios in the surface layer during stagnant and cold-pool episodes. The highly resolved profiles documented the development of approximately week-long ozone production episodes building from regional backgrounds of 40 ppbv to >165 ppbv within a shallow cold pool up to 200 m in depth. Beginning in midmorning, ozone-mixing ratios increased uniformly through the cold pool layer at rates of 5-12 ppbv/h. During ozone events, there was a strong diurnal cycle with each succeeding day accumulating 4-8 ppbv greater than the previous day. The top of the elevated ozone production layer was nearly uniform in altitude across the UB independent of topography. Above the ozone production layer, mixing ratios decreased with height to 400 m above ground level where they approached regional background levels. Rapid clean-out of ozone-rich air occurred within a day when frontal systems brought in fresh air. Solar heating and basin topography led to a diurnal flow pattern in which daytime upslope winds distributed ozone precursors and ozone in the Basin. NOx-rich plumes from a coal-fired power plant in the eastern sector of the Basin did not appear to mix down into the cold pool during this field study.

[Winter surveillance of cold exposure effects on health among the homeless population in the Paris area: data from the Coordinated Health Surveillance of Emergency Department network (Organisation de la surveillance coordonnée des urgences [Oscour(®)])].

PubMed

Rouquette, A; Mandereau-Bruno, L; Baffert, E; Laaidi, K; Josseran, L; Isnard, H

2011-12-01

A program for helping homeless individuals in winter is implemented from November 1(st) to March 31(st) each year in France. Its aim is to prevent morbidity and mortality in this population during cold spells and periods of severe cold. A health surveillance system of the homeless population in the Paris area has been proposed to evaluate the effectiveness of the program and to alert decision-makers if an unusual increase in cold-weather effects is observed. The goal of this study was the creation of an indicator for the proposed surveillance system based on emergency department activity in the Paris area (Oscour(®) Network - Organisation de la surveillance coordonnée des urgences). The winter 2007-2008 computer medical files of 11 emergency departments in the Paris area were examined to confirm diagnosis and ascertain patient-homelessness for each patient visit which was selected from the Oscour(®) database by the patient chief-complaint or diagnosis code referring to hypothermia or frostbites. The proposed indicator is based on the maximization of three criteria: the positive predictive value, the proportion of people identified as being homeless and the number of emergency department visits. A Shewhart control chart was applied to the indicator for the four winters between 2005 and 2009 in the Paris area. Values beyond the statistical threshold would indicate a need for an adjustment to the program strategy. Two hundred and sixteen medical files were analyzed. An indicator was created, "number of emergency department visits of 15 to 69-years-old persons with chief-complaint or diagnosis code referring to hypothermia". It had a positive predictive value estimated near 85 % and identified 61.7 % people as being homeless. In the winter of 2008-2009, the statistical threshold was reached in December during the first cold spell, and again at the beginning of January during a period of severe cold. Our results support the use of this health indicator, alongside social indicators, for optimizing the strategy for helping the homeless population during winter. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Effects of ice and floods on vegetation in streams in cold regions: implications for climate change

PubMed Central

Lind, Lovisa; Nilsson, Christer; Weber, Christine

2014-01-01

Riparian zones support some of the most dynamic and species-rich plant communities in cold regions. A common conception among plant ecologists is that flooding during the season when plants are dormant generally has little effect on the survival and production of riparian vegetation. We show that winter floods may also be of fundamental importance for the composition of riverine vegetation. We investigated the effects of ice formation on riparian and in-stream vegetation in northern Sweden using a combination of experiments and observations in 25 reaches, spanning a gradient from ice-free to ice-rich reaches. The ice-rich reaches were characterized by high production of frazil and anchor ice. In a couple of experiments, we exposed riparian vegetation to experimentally induced winter flooding, which reduced the dominant dwarf-shrub cover and led to colonization of a species-rich forb-dominated vegetation. In another experiment, natural winter floods caused by anchor-ice formation removed plant mimics both in the in-stream and in the riparian zone, further supporting the result that anchor ice maintains dynamic plant communities. With a warmer winter climate, ice-induced winter floods may first increase in frequency because of more frequent shifts between freezing and thawing during winter, but further warming and shortening of the winter might make them less common than today. If ice-induced winter floods become reduced in number because of a warming climate, an important disturbance agent for riparian and in-stream vegetation will be removed, leading to reduced species richness in streams and rivers in cold regions. Given that such regions are expected to have more plant species in the future because of immigration from the south, the distribution of species richness among habitats can be expected to show novel patterns. PMID:25505542

Effects of ice and floods on vegetation in streams in cold regions: implications for climate change.

PubMed

Lind, Lovisa; Nilsson, Christer; Weber, Christine

2014-11-01

Riparian zones support some of the most dynamic and species-rich plant communities in cold regions. A common conception among plant ecologists is that flooding during the season when plants are dormant generally has little effect on the survival and production of riparian vegetation. We show that winter floods may also be of fundamental importance for the composition of riverine vegetation. We investigated the effects of ice formation on riparian and in-stream vegetation in northern Sweden using a combination of experiments and observations in 25 reaches, spanning a gradient from ice-free to ice-rich reaches. The ice-rich reaches were characterized by high production of frazil and anchor ice. In a couple of experiments, we exposed riparian vegetation to experimentally induced winter flooding, which reduced the dominant dwarf-shrub cover and led to colonization of a species-rich forb-dominated vegetation. In another experiment, natural winter floods caused by anchor-ice formation removed plant mimics both in the in-stream and in the riparian zone, further supporting the result that anchor ice maintains dynamic plant communities. With a warmer winter climate, ice-induced winter floods may first increase in frequency because of more frequent shifts between freezing and thawing during winter, but further warming and shortening of the winter might make them less common than today. If ice-induced winter floods become reduced in number because of a warming climate, an important disturbance agent for riparian and in-stream vegetation will be removed, leading to reduced species richness in streams and rivers in cold regions. Given that such regions are expected to have more plant species in the future because of immigration from the south, the distribution of species richness among habitats can be expected to show novel patterns.

Strong Costs and Benefits of Winter Acclimatization in Drosophila melanogaster

PubMed Central

Schou, Mads Fristrup; Loeschcke, Volker; Kristensen, Torsten Nygaard

2015-01-01

Studies on thermal acclimation in insects are often performed on animals acclimated in the laboratory under conditions that are not ecologically relevant. Costs and benefits of acclimation responses under such conditions may not reflect costs and benefits in natural populations subjected to daily and seasonal temperature fluctuations. Here we estimated costs and benefits in thermal tolerance limits in relation to winter acclimatization of Drosophila melanogaster. We sampled flies from a natural habitat during winter in Denmark (field flies) and compared heat and cold tolerance of these to that of flies collected from the same natural population, but acclimated to 25 °C or 13 °C in the laboratory (laboratory flies). We further obtained thermal performance curves for egg-to-adult viability of field and laboratory (25 °C) flies, to estimate possible cross-generational effects of acclimation. We found much higher cold tolerance and a lowered heat tolerance in field flies compared to laboratory flies reared at 25 °C. Flies reared in the laboratory at 13 °C exhibited the same thermal cost-benefit relations as the winter acclimatized flies. We also found a cost of winter acclimatization in terms of decreased egg-to-adult viability at high temperatures of eggs laid by winter acclimatized flies. Based on our findings we suggest that winter acclimatization in nature can induce strong benefits in terms of increased cold tolerance. These benefits can be reproduced in the laboratory under ecologically relevant rearing and testing conditions, and should be incorporated in species distribution modelling. Winter acclimatization also leads to decreased heat tolerance. This may create a mismatch between acclimation responses and the thermal environment, e.g. if temperatures suddenly increase during spring, under current and expected more variable future climatic conditions. PMID:26075607

Strong Costs and Benefits of Winter Acclimatization in Drosophila melanogaster.

PubMed

Schou, Mads Fristrup; Loeschcke, Volker; Kristensen, Torsten Nygaard

2015-01-01

Studies on thermal acclimation in insects are often performed on animals acclimated in the laboratory under conditions that are not ecologically relevant. Costs and benefits of acclimation responses under such conditions may not reflect costs and benefits in natural populations subjected to daily and seasonal temperature fluctuations. Here we estimated costs and benefits in thermal tolerance limits in relation to winter acclimatization of Drosophila melanogaster. We sampled flies from a natural habitat during winter in Denmark (field flies) and compared heat and cold tolerance of these to that of flies collected from the same natural population, but acclimated to 25 °C or 13 °C in the laboratory (laboratory flies). We further obtained thermal performance curves for egg-to-adult viability of field and laboratory (25 °C) flies, to estimate possible cross-generational effects of acclimation. We found much higher cold tolerance and a lowered heat tolerance in field flies compared to laboratory flies reared at 25 °C. Flies reared in the laboratory at 13 °C exhibited the same thermal cost-benefit relations as the winter acclimatized flies. We also found a cost of winter acclimatization in terms of decreased egg-to-adult viability at high temperatures of eggs laid by winter acclimatized flies. Based on our findings we suggest that winter acclimatization in nature can induce strong benefits in terms of increased cold tolerance. These benefits can be reproduced in the laboratory under ecologically relevant rearing and testing conditions, and should be incorporated in species distribution modelling. Winter acclimatization also leads to decreased heat tolerance. This may create a mismatch between acclimation responses and the thermal environment, e.g. if temperatures suddenly increase during spring, under current and expected more variable future climatic conditions.

Households' perception of climate change and human health risks: A community perspective

PubMed Central

2012-01-01

Background Bangladesh has been identified as one of the most vulnerable countries in the world concerning the adverse effects of climate change (CC). However, little is known about the perception of CC from the community, which is important for developing adaptation strategies. Methods The study was a cross-sectional survey of respondents from two villages--one from the northern part and the other from the southern part of Bangladesh. A total of 450 households were selected randomly through multistage sampling completed a semi-structure questionnaire. This was supplemented with 12 focus group discussions (FGDs) and 15 key informant interviews (KIIs). Results Over 95 percent of the respondents reported that the heat during the summers had increased and 80.2 percent reported that rainfall had decreased, compared to their previous experiences. Approximately 65 percent reported that winters were warmer than in previous years but they still experienced very erratic and severe cold during the winter for about 5-7 days, which restricted their activities with very destructive effect on agricultural production, everyday life and the health of people. FGDs and KIIs also reported that overall winters were warmer. Eighty point two percent, 72.5 percent and 54.7 percent survey respondents perceived that the frequency of water, heat and cold related diseases/health problems, respectively, had increased compared to five to ten years ago. FGDs and KIIs respondents were also reported the same. Conclusions Respondents had clear perceptions about changes in heat, cold and rainfall that had occurred over the last five to ten years. Local perceptions of climate variability (CV) included increased heat, overall warmer winters, reduced rainfall and fewer floods. The effects of CV were mostly negative in terms of means of living, human health, agriculture and overall livelihoods. Most local perceptions on CV are consistent with the evidence regarding the vulnerability of Bangladesh to CC. Such findings can be used to formulate appropriate sector programs and interventions. The systematic collection of such information will allow scientists, researchers and policy makers to design and implement appropriate adaptation strategies for CC in countries that are especially vulnerable. PMID:22236490

Passive thermal refugia provided warm water for Florida manatees during the severe winter of 2009-2010

USGS Publications Warehouse

Stith, B.M.; Slone, D.H.; de Wit, M.; Edwards, H.H.; Langtimm, C.A.; Swain, E.D.; Soderqvist, L.E.; Reid, J.P.

2012-01-01

Haloclines induced by freshwater inflow over tidal water have been identified as an important mechanism for maintaining warm water in passive thermal refugia (PTR) used by Florida manatees Trichechus manatus latirostris during winter in extreme southwestern Florida. Record-setting cold during winter 2009–2010 resulted in an unprecedented number of manatee deaths, adding to concerns that PTR may provide inadequate thermal protection during severe cold periods. Hydrological data from 2009–2010 indicate that 2 canal systems in the Ten Thousand Islands (TTI) region acted as PTR and maintained warm bottom-water temperatures, even during severe and prolonged cold periods. Aerial survey counts of live and dead manatees in TTI during the winter of 2009–2010 suggest that these PTR were effective at preventing mass mortality from hypothermia, in contrast to the nearby Everglades region, which lacks similar artificial PTR and showed high manatee carcass counts. Hydrological data from winter 2008–2009 confirmed earlier findings that without haloclines these artificial PTR may become ineffective as warm-water sites. Tidal pumping of groundwater appears to provide additional heat to bottom water during low tide cycles, but the associated thermal inversion is not observed unless salinity stratification is present. The finding that halocline-driven PTR can maintain warm water even under extreme winter conditions suggests that they may have significant potential as warm-water sites. However, availability and conflicting uses of freshwater and other management issues may make halocline-driven PTR unreliable or difficult to manage during winter.

Outdoor Cultivation of Marine Diatoms for Year-Round Production of Biofuels.

PubMed

Matsumoto, Mitsufumi; Nojima, Daisuke; Nonoyama, Tomomi; Ikeda, Kiichi; Maeda, Yoshiaki; Yoshino, Tomoko; Tanaka, Tsuyoshi

2017-03-25

Biofuel production using microalgae is believed to have the advantage of continuous year-round production over crop plants, which have strong seasonality. However, actual year-round production of microalgal lipids using outdoor mass cultivation has rarely been demonstrated. In our previous study, it was demonstrated that the oleaginous diatom, Fistulifera solaris , was culturable in outdoor bioreactors from spring to autumn, whereas biomass and lipid production in winter failed because F. solaris did not grow below 15 °C. Therefore, another candidate strain that is culturable in winter is required. In this study, a cold-tolerant diatom, Mayamaea sp. JPCC CTDA0820, was selected as a promising candidate for biofuel production in winter. Laboratory-scale characterization revealed that this diatom was culturable at temperatures as low as 10 °C. Subsequently, F. solaris (April-October) and Mayamaea sp. JPCC CTDA0820 (November-March) were cultured in outdoor open-pond bioreactors, wherein year-round production of diatom lipids was successfully demonstrated. The maximal values of areal productivities of biomass and lipids reached to 9.79 and 1.80 g/(m² day) for F. solaris , and 8.62 and 0.92 g/(m² day) for Mayamaea sp. JPCC CTDA0820, respectively. With the combined use of these two diatom species, stable year-round production of microalgal lipids became possible.

Evaluation of large-scale meteorological patterns associated with temperature extremes in the NARCCAP regional climate model simulations

NASA Astrophysics Data System (ADS)

Loikith, Paul C.; Waliser, Duane E.; Lee, Huikyo; Neelin, J. David; Lintner, Benjamin R.; McGinnis, Seth; Mearns, Linda O.; Kim, Jinwon

2015-12-01

Large-scale meteorological patterns (LSMPs) associated with temperature extremes are evaluated in a suite of regional climate model (RCM) simulations contributing to the North American Regional Climate Change Assessment Program. LSMPs are characterized through composites of surface air temperature, sea level pressure, and 500 hPa geopotential height anomalies concurrent with extreme temperature days. Six of the seventeen RCM simulations are driven by boundary conditions from reanalysis while the other eleven are driven by one of four global climate models (GCMs). Four illustrative case studies are analyzed in detail. Model fidelity in LSMP spatial representation is high for cold winter extremes near Chicago. Winter warm extremes are captured by most RCMs in northern California, with some notable exceptions. Model fidelity is lower for cool summer days near Houston and extreme summer heat events in the Ohio Valley. Physical interpretation of these patterns and identification of well-simulated cases, such as for Chicago, boosts confidence in the ability of these models to simulate days in the tails of the temperature distribution. Results appear consistent with the expectation that the ability of an RCM to reproduce a realistically shaped frequency distribution for temperature, especially at the tails, is related to its fidelity in simulating LMSPs. Each ensemble member is ranked for its ability to reproduce LSMPs associated with observed warm and cold extremes, identifying systematically high performing RCMs and the GCMs that provide superior boundary forcing. The methodology developed here provides a framework for identifying regions where further process-based evaluation would improve the understanding of simulation error and help guide future model improvement and downscaling efforts.

The overwintering biology of the acorn weevil, Curculio glandium in southwestern Ontario.

PubMed

Udaka, Hiroko; Sinclair, Brent J

2014-08-01

The acorn weevil, Curculio glandium, is a widespread predator of acorns in eastern North America that overwinters in the soil as a larva. It is possible that low temperatures limit its northern geographic range, so we determined the cold tolerance strategy, seasonal variation in cold tolerance, and explored the physiological plasticity of overwintering larvae. Weevil larvae were collected from acorns of red and bur oak from Pelee Island, southwestern Ontario in fall 2010 and 2011. C. glandium larvae are freeze avoidant and larvae collected from bur oak acorns had lower supercooling points (SCPs: -7.6±0.36°C, LT50: -7.2°C) than those collected from red oak acorns (SCPs: -6.1±0.40°C, LT50: -6.1°C). In the winter of 2010-2011, SCPs and water content decreased, however these changes did not occur in 2011-2012, when winter soil temperatures fluctuated greatly in the absence of the buffering effect of snow. To examine whether larvae utilize cryoprotective dehydration, larvae from red oak acorns were exposed to -5°C in the presence of ice for seven days. These conditions decreased the SCP without affecting water content, suggesting that SCP and water content are not directly coupled. Finally, long-term acclimation at 0°C for six weeks slightly increased cold tolerance but also did not affect water content. Thus, although larval diet affects cold tolerance, there is limited plasticity after other treatments. The soil temperatures we observed were not close to lethal limits, although we speculate that soil temperatures in northerly habitats, or in years of reduced snow cover, has the potential to cause mortality in the field. Copyright © 2014 Elsevier Ltd. All rights reserved.

Herbicides induce change in metabolic and genetic diversity of bacterial community from a cold oligotrophic lake.

PubMed

Aguayo, P; González, C; Barra, R; Becerra, J; Martínez, M

2014-03-01

Pristine cold oligotrophic lakes show unique physical and chemical characteristics with permanent fluctuation in temperature and carbon source availability. Incorporation of organic toxic matters to these ecosystems could alter the bacterial community composition. Our goal was to assess the effects of simazine (Sz) and 2,4 dichlorophenoxyacetic acid (2,4-D) upon the metabolic and genetic diversity of the bacterial community in sediment samples from a pristine cold oligotrophic lake. Sediment samples were collected in winter and summer season, and microcosms were prepared using a ration 1:10 (sediments:water). The microcosms were supplemented with 0.1 mM 2,4-D or 0.5 mM Sz and incubated for 20 days at 10 °C. Metabolic diversity was evaluated by using the Biolog Ecoplate™ system and genetic diversity by 16S rDNA amplification followed by denaturing gradient gel electrophoresis analysis. Total bacterial counts and live/dead ratio were determined by epifluorescence microscopy. The control microcosms showed no significant differences (P > 0.05) in both metabolic and genetic diversity between summer and winter samples. On the other hand, the addition of 2,4-D or Sz to microcosms induces statistical significant differences (P < 0.05) in metabolic and genetic diversity showing the prevalence of Actinobacteria group which are usually not detected in the sediments of these non-contaminated lacustrine systems. The obtained results suggest that contaminations of cold pristine lakes with organic toxic compounds of anthropic origin alter their homeostasis by inhibiting specific susceptible bacterial groups. The concomitant increase of usually low representative bacterial groups modifies the bacterial composition commonly found in this pristine lake.

The effects of a mid-winter 8-week course of sub-sunburn sunbed exposures on tanning, vitamin D status and colds.

PubMed

de Gruijl, Frank R; Pavel, Stan

2012-12-01

Like UV irradiation, which generates vitamin D(3) in the skin, the hormonally active metabolite, 1,25-dihydroxyvitamin D(3), boosts innate immunity against viruses and bacteria. Epidemiologic studies have found high vitamin D levels to be associated with lower risk of infections of the upper respiratory tract (colds). We have therefore performed an intervention study in 105 young adults (ages 18-30 years; 91% female) over a mid-winter 8-week period (January-March 2010). The participants were randomised to 3 groups: (A) subjected to 3 times a week sub-sunburn sunbed exposure (n = 35), (B) daily vitamin D supplementation, @ 1000 IU (n = 37), and (C) a control group without any intervention (n = 33). The mean serum level of 25-hydroxyvitamin D (25(OH)D) dropped from 62 to 55 nmol l(-1) in group C, while these levels rose from 62 to 109 and from 58 to 93 nmol l(-1) in groups A and B, respectively (p < 0.001). The skin on the chest darkened significantly in group A (mean difference in lightness, L*, equalled -5.7, p < 0.001), correlating significantly, but weakly, with increases in 25(OH)D (3.3 nmol l(-1) per unit drop in L*, R(2) = 0.17, p = 0.014). The percentage of self-reported colds with proper signs and symptoms was only slightly and not significantly reduced in groups A and B in comparison to group C: 57 and 51 versus 67%, respectively. Hence, the sub-sunburn sunbed treatment was effective in tanning and increasing the 25(OH)D serum level, more so than 1000 IU per day, but had no appreciable effect on colds.

The Asian-Bering-North American teleconnection: seasonality, maintenance, and climate impact on North America

NASA Astrophysics Data System (ADS)

Yu, Bin; Lin, H.; Wu, Z. W.; Merryfield, W. J.

2018-03-01

The Asian-Bering-North American (ABNA) teleconnection index is constructed from the normalized 500-hPa geopotential field by excluding the Pacific-North American pattern contribution. The ABNA pattern features a zonally elongated wavetrain originating from North Asia and flowing downstream across Bering Sea and Strait towards North America. The large-scale teleconnection is a year-round phenomenon that displays strong seasonality with the peak variability in winter. North American surface temperature and temperature extremes, including warm days and nights as well as cold days and nights, are significantly controlled by this teleconnection. The ABNA pattern has an equivalent barotropic structure in the troposphere and is supported by synoptic-scale eddy forcing in the upper troposphere. Its associated sea surface temperature anomalies exhibit a horseshoe-shaped structure in the North Pacific, most prominent in winter, which is driven by atmospheric circulation anomalies. The snow cover anomalies over the West Siberian plain and Central Siberian Plateau in autumn and spring and over southern Siberia in winter may act as a forcing influence on the ABNA pattern. The snow forcing influence in winter and spring can be traced back to the preceding season, which provides a predictability source for this teleconnection and for North American temperature variability. The ABNA associated energy budget is dominated by surface longwave radiation anomalies year-round, with the temperature anomalies supported by anomalous downward longwave radiation and damped by upward longwave radiation at the surface.

Patterns of cold-air drainage and microclimate in mid-latitude versus high-latitude mountains: contrasts and implications for climate change (Invited)

NASA Astrophysics Data System (ADS)

Pepin, N. C.

2009-12-01

Predictions of current spatial patterns of climate are difficult in areas of complex relief in all parts of the world, because of the interweaving influences of topography, elevation and aspect. These influences vary temporally as a result of the seasonal and diurnal cycles in radiation balance. In periods of negative energy balance, surface decoupling can occur as cold air drainage develops low-level temperature inversions, and the surface temperature regime beneath the inversion becomes divorced from free atmospheric forcing. Both the spatial scale and temporal persistence of this decoupling vary according to latitude, and although the physical processes that influence inversion formation are similar in polar areas and mid-latitude mountains, the contrasting seasonal and diurnal forcings make the end results very different. Examples are contrasted from detailed field temperature measurements (~50 sites per field area) taken over several years in areas of complex relief in the eastern Pyrenees (~42.5 deg N), the Oregon Cascades (also ~42.5 deg N) and Finnish Lapland (70 deg N and above the Arctic circle). In the former two locations decoupling is mostly diurnally driven, and small-scale topography is important in mediating the effects. Summer decoupling is brief and spatially limited, whereas winter decoupling can be more spatially extensive. There are strong relationships between synoptic conditions, as measured by objective flow indices at the 700 mb level (derived from NCEP/NCAR reanalysis fields) and the patterns of decoupling, which allow us to assess the effects of past and potential future circulation change on spatial patterns of future climate warming. In Finnish Lapland the decoupling regime most clearly approaches the mid-latitude pattern around the equinoxes when there are clear day and night periods. In winter and summer however (the polar night and polar day) with the muting of the diurnal cycle, processes are more poorly understood. Winter cold pools can develop and strengthen over days until eventually they extend over and above the topography. Strangely, there are also indistinct relationships with circulation indices at this time. While build-up can take days, destruction is often immediate and is dynamically forced. In summer, localized decoupling occurs on clear nights even though the sun is above the horizon, but micro-scale patterns are different than in mid-latitudes. The above comparison shows that polar areas are very different in their micro-temperature regimes than mid-latitude mountains and in their relationships of these regimes with circulation. Thus we expect detailed spatial patterns of climate change may be very different in the two regions.

Essential Outdoor Sun Safety Tips for Winter

MedlinePlus

... the risk for damage. Both snow and strong wind can wear away sunscreen and reduce its effectiveness, ... protect your skin from the bitter cold, heavy winds and winter sun, follow these important sun protection ...

Arctic Ozone Depletion from UARS MLS Measurements

NASA Technical Reports Server (NTRS)

Manney, G. L.

1995-01-01

Microwave Limb Sounder (MLS) measurements of ozone during four Arctic winters are compared. The evolution of ozone in the lower stratosphere is related to temperature, chlorine monoxide (also measured by MLS), and the evolution of the polar vortex. Lagrangian transport calculations using winds from the United Kingdom Meteorological Office's Stratosphere-Troposphere Data Assimilation system are used to estimate to what extent the evolution of lower stratospheric ozone is controlled by dynamics. Observations, along with calculations of the expected dynamical behavior, show evidence for chemical ozone depletion throughout most of the Arctic lower stratospheric vortex during the 1992-93 middle and late winter, and during all of the 1994-95 winter that was observed by MLS. Both of these winters were unusually cold and had unusually cold and had unusually strong Arctic polar vortices compared to meteorological data over the past 17 years.

[Temporal and spatial change of climate resources and meteorological disasters under climate change during winter crop growing season in Guangdong Province, China.

PubMed

Wang, Hua; Chen, Hui Hua; Tang, Li Sheng; Wang, Juan Huai; Tang, Hai Yan

2018-01-01

Trend analysis method was applied to analyze the general variation characteristics of the climate resources and meteorological disasters of growing season of the winter planting in Guangdong before (1961-1996) and after climate warming (1997-2015). Percentile method was employed to determine thresholds for extreme cold and drought in major planting regions, and the characteristics of extreme disasters since climate warming were analyzed. The results showed that, by comparing 1997-2015 with 1961-1996, the heat value in winter growing season increased significantly. The belt with a higher heat value, where the average temperature was ≥15 ℃ and accumulated temperature was ≥2200 ℃·d, covered the main winter production regions as Shaoguan, Zhanjiang, Maoming, Huizhou, Meizhou and Guangzhou. Meanwhile, the precipitation witnessed a slight increase. The regions with precipitations of 250-350 mm included Zhanjiang, Maoming, Huizhou, Guangzhou and Meizhou. Chilling injury in the winter planting season in the regions decreased, the belt with an accumulated chilling of <2 ℃·d covered the major geographic parts of the involved regions as Zhanjiang, Maoming, Guangzhou and Huizhou; and the belt with an accumulated chilling of 8-16 ℃·d covered the major geographic parts of Shaoguan and Meizhou. Meanwhile, the drought days decreased, the belt with drought days ≥50 included the major geographic parts of Zhanjiang, Maoming, Huizhou, Guangzhou and the belt with drought days <50 included the major geographic parts of Shaoguan. The typical case of the extreme disasters showed that the extreme chilling injury and drought in the main producing regions should not be overlooked. Maoming, Huizhou and Meizhou were at higher risk of extreme chilling injury, followed by Shaoguan and Guangzhou. Zhanjiang and Maoming faced the highest risk of extreme drought, Huizhou and Guangzhou took the second place, Shaoguan and Meizhou went last. During 1997-2015, the heat of winter season increased significantly, the trend of chilling and drought decreased, however, the extreme disasters occurred frequently and the risks were higher in winter production areas. It was suggested that the winter planting should be closely integrated with climate resources and the occurrence law of meteorological disasters in growing season.

A new approach to modeling temperature-related mortality: Non-linear autoregressive models with exogenous input.

PubMed

Lee, Cameron C; Sheridan, Scott C

2018-07-01

Temperature-mortality relationships are nonlinear, time-lagged, and can vary depending on the time of year and geographic location, all of which limits the applicability of simple regression models in describing these associations. This research demonstrates the utility of an alternative method for modeling such complex relationships that has gained recent traction in other environmental fields: nonlinear autoregressive models with exogenous input (NARX models). All-cause mortality data and multiple temperature-based data sets were gathered from 41 different US cities, for the period 1975-2010, and subjected to ensemble NARX modeling. Models generally performed better in larger cities and during the winter season. Across the US, median absolute percentage errors were 10% (ranging from 4% to 15% in various cities), the average improvement in the r-squared over that of a simple persistence model was 17% (6-24%), and the hit rate for modeling spike days in mortality (>80th percentile) was 54% (34-71%). Mortality responded acutely to hot summer days, peaking at 0-2 days of lag before dropping precipitously, and there was an extended mortality response to cold winter days, peaking at 2-4 days of lag and dropping slowly and continuing for multiple weeks. Spring and autumn showed both of the aforementioned temperature-mortality relationships, but generally to a lesser magnitude than what was seen in summer or winter. When compared to distributed lag nonlinear models, NARX model output was nearly identical. These results highlight the applicability of NARX models for use in modeling complex and time-dependent relationships for various applications in epidemiology and environmental sciences. Copyright © 2018 Elsevier Inc. All rights reserved.

Risk of hospitalization for fire-related burns during extreme cold weather.

PubMed

Ayoub, Aimina; Kosatsky, Tom; Smargiassi, Audrey; Bilodeau-Bertrand, Marianne; Auger, Nathalie

2017-10-01

Environmental factors are important predictors of fires, but no study has examined the association between outdoor temperature and fire-related burn injuries. We sought to investigate the relationship between extremely cold outdoor temperatures and the risk of hospitalization for fire-related burns. We carried out a time-stratified case-crossover study of 2470 patients hospitalized for fire-related burn injuries during cold months between 1989 and 2014 in Quebec, Canada. The main exposure was the minimum outdoor temperature on the day of and the day before the burn. We computed odds ratios (OR) and 95% confidence intervals (CI) to evaluate the relationship between minimum temperature and fire-related burns, and assessed how associations varied across sex and age. Exposure to extreme cold temperature was associated with a significantly higher risk of hospitalization for fire-related burns. Compared with 0°C, exposure to a minimum temperature of -30°C was associated with an OR of 1.51 (95% CI 1.22-1.87) for hospitalization for fire-related burns. The associations were somewhat stronger for women, youth, and the elderly. Compared with 0°C, a minimum temperature of -30°C was associated with an OR for fire-related burn hospitalization of 1.65 for women (95% CI 1.13-2.40), 1.60 for age < 25 years (95% CI 1.02-2.52), and 1.73 for age ≥ 65 years (95% CI 1.08-2.77). Extremely cold outdoor temperature is a risk factor for fire-related burns. Measures to prevent fires should be implemented prior to the winter season, and enhanced during extreme cold. Copyright © 2017 Elsevier Inc. All rights reserved.

Physiological processes during winter dormancy and their ecological significance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Havranek, W.M.; Tranquillini, W.

1995-07-01

Lengthy and severe winters require that trees in the forests of boreal and mountain zones undergo winter dormancy. Physiologically, a high resistance to subfreezing temperatures and concomitant dehydration are necessary. To accomplish this dormancy, both physiological and structural changes are needed at the cellular level that require induction by endogenous and photoperiodic control early in autumn. Endogenous rhythmicity promotes cold hardening in early autumn and the persistence of hardiness throughout the winter. Numerous physiological functions are maintained at a reduced level, or become completely inhibited during true winter dormancy. Winter hardiness also includes the capability to minimize water loss effectivelymore » when water uptake is severely impeded or impossible. Anatomical features such as tracheids act to minimize xylem embolism during frequent freeze-thaw cycles, and {open_quotes}crown{close_quotes} tissues enable buds to stay in a dehydrated and, thus, more resistant state during winter. Both these structural features are adaptations that contribute to the dominance of conifers in cold climates. Interestingly, deciduous tree species rather than evergreen conifers dominate in the most severe winter climates, although it is not clear whether limitations during winter, during the summer growth period, or during both are most limiting to conifer tree ecology. Additional work that evaluates the importance of winter and summer growth restriction, and their interaction, is needed before a comprehensive understanding of conifer tree ecophysiology will be possible.« less

Characteristics of Winter Surface Air Temperature Anomalies in Moscow in 1970-2016 under Conditions of Reduced Sea Ice Area in the Barents Sea

NASA Astrophysics Data System (ADS)

Shukurov, K. A.; Semenov, V. A.

2018-01-01

On the basis of observational data on daily mean surface air temperature (SAT) and sea ice concentration (SIC) in the Barents Sea (BS), the characteristics of strong positive and negative winter SAT anomalies in Moscow have been studied in comparison with BS SIC data obtained in 1949-2016. An analysis of surface backward trajectories of air-particle motions has revealed the most probable paths of both cold and warm air invasions into Moscow and located regions that mostly affect strong winter SAT anomalies in Moscow. Atmospheric circulation anomalies that cause strong winter SAT anomalies in Moscow have been revealed. Changes in the ways of both cold and warm air invasions have been found, as well as an increase in the frequency of blocking anticyclones in 2005-2016 when compared to 1970-1999. The results suggest that a winter SIC decrease in the BS in 2005-2016 affects strong winter SAT anomalies in Moscow due to an increase in the frequency of occurrence of blocking anticyclones to the south of and over the BS.

Winter Storms and Extreme Cold

MedlinePlus

... your home to keep out the cold with insulation, caulking, and weather stripping. Learn how to keep ... and grills outdoors and away from windows. Never heat your home with a gas stovetop or oven. ...

A weather regime characterisation of Irish wind generation and electricity demand in winters 2009–11

NASA Astrophysics Data System (ADS)

Cradden, Lucy C.; McDermott, Frank

2018-05-01

Prolonged cold spells were experienced in Ireland in the winters of 2009–10 and 2010–11, and electricity demand was relatively high at these times, whilst wind generation capacity factors were low. Such situations can cause difficulties for an electricity system with a high dependence on wind energy. Studying the atmospheric conditions associated with these two winters offers insights into the large-scale drivers for cold, calm spells, and helps to evaluate if they are rare events over the long-term. The influence of particular atmospheric patterns on coincidental winter wind generation and weather-related electricity demand is investigated here, with a focus on blocking in the North Atlantic/European sector. The occurrences of such patterns in the 2009–10 and 2010–11 winters are examined, and 2010–11 in particular was found to be unusual in a long-term context. The results are discussed in terms of the relevance to long-term planning and investment in the electricity system.

Predictability of the European heat and cold waves

NASA Astrophysics Data System (ADS)

Lavaysse, Christophe; Naumann, Gustavo; Alfieri, Lorenzo; Salamon, Peter; Vogt, Jürgen

2018-06-01

Heat and cold waves may have considerable human and economic impacts in Europe. Recent events, like the heat waves observed in France in 2003 and Russia in 2010, illustrated the major consequences to be expected. Reliable Early Warning Systems for extreme temperatures would, therefore, be of high value for decision makers. However, they require a clear definition and robust forecasts of these events. This study analyzes the predictability of heat and cold waves over Europe, defined as at least three consecutive days of {T}_{min} and {T}_{max} above the quantile Q90 (under Q10), using the extended ensemble system of ECMWF. The results show significant predictability for events within a 2-week lead time, but with a strong decrease of the predictability during the first week of forecasts (from 80 to 40% of observed events correctly forecasted). The scores show a higher predictive skill for the cold waves (in winter) than for the heat waves (in summer). The uncertainties and the sensitivities of the predictability are discussed on the basis of tests conducted with different spatial and temporal resolutions. Results demonstrate the negligible effect of the temporal resolution (very few errors due to bad timing of the forecasts), and a better predictability of large-scale events. The onset and the end of the waves are slightly less predictable with an average of about 35% (30%) of observed heat (cold) waves onsets or ends correctly forecasted with a 5-day lead time. Finally, the forecasted intensities show a correlation of about 0.65 with those observed, revealing the challenge to predict this important characteristic.

Cryoprotection in dampwood termites (Termopsidae, Isoptera).

PubMed

Lacey, Michael J; Lenz, Michael; Evans, Theodore A

2010-01-01

In contrast to the majority of the Order, the dampwood termites of the family Termopsidae found in colder regions can experience frost and snow, either in cool temperate areas at high latitudes (45 degrees ), or alpine areas at high elevations (>1000m). This suggests that dampwood termites are adapted to cold climates. We investigated this hypothesis in two dampwood termites, Porotermes adamsoni Froggatt and Stolotermes victoriensis Hill. We measured nest temperatures and atmospheric temperatures of their alpine habitat during winter, and measured survival and recovery at subzero temperatures. We also determined the minimum temperature at which these species remain active and the LT50 values. We used a novel gas chromatographic strategy to examine eight metabolites from individuals of both species collected in winter and summer to identify possible cryoprotectants. Both P. adamsoni and S. victoriensis had significantly higher levels of trehalose, a known cryoprotectant, in winter than in summer; in addition S. victoriensis also had higher levels of unsaturated fatty acid ligands in winter than in summer, consistent with patterns observed for cold adaptation in other organisms. These results are the first to reveal that dampwood termites are adapted to cold climates and use trehalose and unsaturated lipids as cryoprotectants.

Seasonal movements, migratory behavior, and site fidelity of West Indian manatees along the Atlantic coast of the United States

USGS Publications Warehouse

Deutsch, C.J.; Reid, J.P.; Bonde, R.K.; Easton, Dean E.; Kochman, H.I.; O'Shea, T.J.

2003-01-01

The West Indian manatee (Trichechus manatus) is endangered by human activities throughout its range, including the U.S. Atlantic coast where habitat degradation from coastal development and manatee deaths from watercraft collisions have been particularly severe. We radio-tagged and tracked 78 manatees along the east coast of Florida and Georgia over a 12-year period (1986-1998). Our goals were to characterize the seasonal movements, migratory behavior, and site fidelity of manatees in this region in order to provide information for the development of effective conservation strategies. Most study animals were tracked remotely with the Argos satellite system, which yielded a mean (SD) of 3.7 (1.6) locations per day; all were regularly tracked in the field using conventional radiotelemetry methods. The combined data collection effort yielded >93,000 locations over nearly 32,000 tag-days. The median duration of tracking was 8.3 months per individual, but numerous manatees were tracked over multiple years (max = 6.8 years). Most manatees migrated seasonally over large distances between a northerly warm-season range and a southerly winter range (median one-way distance = 280 km, max = 830 km), but 12% of individuals were resident in a relatively small area (2,300 km of coastline between southeastern Florida and Rhode Island. No study animals journeyed to the Gulf coast of Florida. Regions heavily utilized by tagged manatees included: Fernandina Beach, FL to Brunswick, GA in the warm season; northern Biscayne Bay to Port Everglades, FL in the winter; and central coastal Florida, especially the Banana River and northern Indian River lagoons, in all seasons. Daily travel rate, defined as the distance between successive mean daily locations, averaged 2.5 km (SD = 1.7), but this varied with season, migratory pattern, and sex. Adult males traveled a significantly greater distance per day than did adult females for most of the warm season, which corresponded closely with the principal period of breeding activity, but there was no difference between the sexes in daily travel rate during the winter. The timing of seasonal migrations differed markedly between geographic regions. Most long-distance movements in the southern half of the study area occurred between November and March in response to changing temperatures, whereas most migrations in the northern region took place during the warmer, non-winter months. Manatees left their warm-season range in central Florida in response to cold fronts that dropped water temperatures by an average of 2.0??C over the 24-hr period preceding departure. Water temperature at departure from the warm-season range averaged 19??C, but varied among individuals (16-22??C) and was not related to body size or female reproductive status. The presence of industrial warm-water effluents permitted many manatees to overwinter north of their historic winter range, and for some migrants this delayed autumn migrations and facilitated earlier spring migrations. Southward autumn and northward spring migrations lasted an average of 10 and 15 days at mean rates of 33.5 (SD = 7.6) and 27.3 (SD = 10.5) km/day, respectively. The highest rate of travel during migration was 87 km/day (3.6 km/hr) during winter. Manatees overwintering in southeastern Florida often traveled north during mild weather - sometimes reaching their warm-season range - only to return south again with the next major cold front. Manatees were consistent in their seasonal movement patterns across years and showed strong fidelity, to warm-season and winter ranges. Within a season, individuals usually occupied only 1 or 2 core use areas that encompassed about 90% of daily locations. Most manatees returned faithfully to the same seasonal ranges year after year (median distance between range centers was <5 km between years). Seasonal movements of 4 immature manatees tracked as calves with their mothers

Halting Hypothermia: Cold Can Be Dangerous

MedlinePlus

... who spends much time outdoors in very cold weather can get hypothermia. But hypothermia can happen anywhere— ... just outside and not just in bitter winter weather. It can strike when temperatures are cool—for ...

Winter sports athletes: long-term effects of cold air exposure.

PubMed

Sue-Chu, Malcolm

2012-05-01

Athletes such as skaters and skiers inhale large volumes of cold air during exercise and shift from nasal to mouth breathing. Endurance athletes, like cross-country skiers, perform at 80% or more of their maximal oxygen consumption and have minute ventilations in excess of 100 l/min. Cold air is always dry, and endurance exercise results in loss of water and heat from the lower respiratory tract. In addition, athletes can be exposed to indoor and outdoor pollutants during the competitive season and during all-year training. Hyperpnoea with cold dry air represents a significant environmental stress to the airways. Winter athletes have a high prevalence of respiratory symptoms and airway hyper-responsiveness to methacholine and hyperpnoea. The acute effects of exercise in cold air are neutrophil influx as demonstrated in lavage fluid and airway epithelial damage as demonstrated by bronchoscopy. Upregulation of pro-inflammatory cytokines has been observed in horses. Chronic endurance training damages the epithelium of the small airways in mice. Airway inflammation has been observed on bronchoscopy of cross-country skiers and in dogs after a 1100-mile endurance race in Alaska. Neutrophilic and lymphocytic inflammation with remodelling is present in bronchial biopsies from skiers. Repeated peripheral airway hyperpnoea with dry air causes inflammation and remodelling in dogs. As it is currently unknown if these airway changes are reversible upon cessation of exposure, preventive measures to diminish exposure of the lower airways to cold air should be instituted by all winter sports athletes.

Vernalization Requirement and the Chromosomal VRN1-Region can Affect Freezing Tolerance and Expression of Cold-Regulated Genes in Festuca pratensis

PubMed Central

Ergon, Åshild; Melby, Tone I.; Höglind, Mats; Rognli, Odd A.

2016-01-01

Plants adapted to cold winters go through annual cycles of gain followed by loss of freezing tolerance (cold acclimation and deacclimation). Warm spells during winter and early spring can cause deacclimation, and if temperatures drop, freezing damage may occur. Many plants are vernalized during winter, a process making them competent to flower in the following summer. In winter cereals, a coincidence in the timing of vernalization saturation, deacclimation, downregulation of cold-induced genes, and reduced ability to reacclimate, occurs under long photoperiods and is under control of the main regulator of vernalization requirement in cereals, VRN1, and/or closely linked gene(s). Thus, the probability of freezing damage after a warm spell may depend on both vernalization saturation and photoperiod. We investigated the role of vernalization and the VRN1-region on freezing tolerance of meadow fescue (Festuca pratensis Huds.), a perennial grass species. Two F2 populations, divergently selected for high and low vernalization requirement, were studied. Each genotype was characterized for the copy number of one of the four parental haplotypes of the VRN1-region. Clonal plants were cold acclimated for 2 weeks or vernalized/cold acclimated for a total of 9 weeks, after which the F2 populations reached different levels of vernalization saturation. Vernalized and cold acclimated plants were deacclimated for 1 week and then reacclimated for 2 weeks. All treatments were given at 8 h photoperiod. Flowering response, freezing tolerance and expression of the cold-induced genes VRN1, MADS3, CBF6, COR14B, CR7 (BLT14), LOS2, and IRI1 was measured. We found that some genotypes can lose some freezing tolerance after vernalization and a deacclimation–reacclimation cycle. The relationship between vernalization and freezing tolerance was complex. We found effects of the VRN1-region on freezing tolerance in plants cold acclimated for 2 weeks, timing of heading after 9 weeks of vernalization, expression of COR14B, CBF6, and LOS2 in vernalized and/or deacclimated treatments, and restoration of freezing tolerance during reacclimation. While expression of VRN1, COR14B, CBF6, LOS2, and IRI1 was correlated, CR7 was associated with vernalization requirement by other mechanisms, and appeared to play a role in freezing tolerance in reacclimated plants. PMID:26941767

A teleconnection study of interannual sea surface temperature fluctuations in the northern North Atlantic and precipitation and runoff over Western Siberia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, S.; Mysak, L.A.

The spatial distributions of northern North Atlantic sea surface temperature and the high-latitude Northern Hemisphere sea level pressure anomalies averaged over six consecutive warm SST winters (1951-1956) and six consecutive cold SST winters (1971-1976) are examined. Three SLP anomaly difference (i.e., warm - cold winters) centers, significant at the 5% level, are observed over the northern North Atlantic, Europe, and western Siberia. This anomaly pattern is consistent in principle with what was identified in a related analyses by Palmer and Sun, who used composite data from selected winter months. The SLP difference centers over the northern North Atlantic and westernmore » Siberia are in phase. The impact of the latter center upon the runoff from the underlying Ob and Yenisey rivers and especially the teleconnection between SST anomalies in the northern North Atlantic and runoff of those two rivers via the atmosphere are investigated. The temporal cross-correlation analyses of 50 years (1930-1979) of records of SST, precipitation, and runoff anomalies indicate that the winter SST anomalies in the northern North Atlantic are significantly correlated with the winter and following summer runoff fluctuations of the Ob and Yenisey rivers. Positive (negative) northern North Atlantic SST anomalies are related to less (more) precipitation, and hence, less (more) runoff, over western Siberia. Discussions of possible physical mechanisms and processes that lead to the above relationships are attempted. The analyses of spatial distributions of precipitation in the warm and cold SST winters suggest that precipitation fluctuations over Europe and western Siberia may be affected by shifts of cyclone tracks associated with the SST variations in the northern North Atlantic. 27 refs., 9 figs.« less

Late Holocene Winter Temperatures in the Eastern Mediterranean and Their Relation to Cultural Changes: The Kocain Cave Record

NASA Astrophysics Data System (ADS)

Mert Gokturk, Ozan; Fleitmann, Dominik; Badertscher, Seraina; Cheng, Hai; Edwards, R. Lawrence; Tuysuz, Okan

2015-04-01

Based on the δ13C profile of a stalagmite from the Kocain Cave in southern Turkey, we present a new proxy record of winter temperatures for the Eastern Mediterranean covering the last ~5500 years. In this region precisely-dated and highly-resolved paleoclimate records for the cold season are almost non-existent. The comparison of the most recent part of the Kocain record with meteorological observations reveals that stalagmite δ13C values correlate on decadal scale with the amount of snowfall above the cave, which correlates well with average winter temperatures. More negative δ13C values indicate higher drip rates in the cave due to more efficient infiltration during snowmelt above Kocain Cave, during colder winters. Cold periods in the rest of the record coincide with widespread glacier advances, especially with the ones in the Alps during the Bronze Age - Iron Age transition (from ~1000 BC on) and the late Little Ice Age (~1600 to 1850 AD). This further supports the interpretation of δ13C as a temperature proxy. Although winters during the Medieval Climate Anomaly were not continuously warm in the Eastern Mediterranean, winter warmth in the modern era was matched or exceeded several times in the last ~5700 years, especially during the time of Minoan civilization in Crete (~2700 to 1200 BC). Moreover, we provide evidence for the important role of winter cold and drought in the events leading to the unrest in the 16th century Anatolia during the Ottoman rule. Kocain Cave record brings insights into several climatically-induced historical changes in the Eastern Mediterranean, and has the potential to be a key record in a region with a long and vibrant history.

Adaptation to exercise in the cold.

PubMed

Shephard, R J

1985-01-01

The winter athlete has several potential tactics for sustaining body temperature in the face of severe cold. An increase in the intensity of physical activity may be counter-productive because of increased respiratory heat loss, increased air or water movement over the body surface, and a pumping of air or water beneath the clothing. Shivering can generate heat at a rate of 10 to 15 kJ/min, but it impairs skilled performance, while the resultant glycogen usage hastens the onset of fatigue and mental confusion. Non-shivering thermogenesis could arise in either brown adipose tissue or white fat. Brown adipose tissue generates heat by the action of free fatty acids in uncoupling mitochondrial electron transport, and by noradrenaline-induced membrane depolarisation and sodium pumping. The existence of brown adipose tissue in human adults is controversial, and although there are theoretical mechanisms of heat production in white fat, their contribution to the maintenance of body temperature is small. Acclimatisation to cold develops over the course of about 10 days, and in humans the primary change is an insulative, hypothermic type of response; this reflects the intermittent nature of most occupational and athletic exposures to cold. Nevertheless, with more sustained exposure to cold air or water, humans can apparently develop the humoral type of acclimatisation described in small mammals, with an increased output of noradrenaline and/or thyroxine. The associated mobilisation of free fatty acids suggests the possibility of using winter sport as a pleasant method of treating obesity. In men, a combination of moderate exercise and facial cooling induces a substantial fat loss over a 1- to 2-week period, with an associated ketonuria, proteinuria, and increase of body mass. Possible factors contributing to this fat loss include: (a) a small energy deficit; (b) the energy cost of synthesising new lean tissue; (c) energy loss through the storage and excretion of ketone bodies; (d) catecholamine-induced 'futile' metabolic cycles with increased resting metabolism; and (e) a specific reaction to cold dehydration. Current limitations for the clinical application of such treatment include uncertainty regarding optimal environmental conditions, concern over possible pathological reactions to cold, and suggestions of a less satisfactory fat mobilisation in female patients. Possible interactions between physical fitness and metabolic reactions to cold remain controversial.(ABSTRACT TRUNCATED AT 400 WORDS)

Research on best practices for winter weather operations.

DOT National Transportation Integrated Search

2012-10-01

There is a growing need to identify actionable practices relative to winter weather operations. Because of the : potential and inherent hazards during cold weather, it has become increasingly important to ensure that these : practices can be effectiv...

7 CFR 760.702 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms, ice storms, snow, blizzard, hurricane, typhoons, tropical storms, and cold wet weather. A disaster..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms...

7 CFR 760.702 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms, ice storms, snow, blizzard, hurricane, typhoons, tropical storms, and cold wet weather. A disaster..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms...

7 CFR 760.702 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms, ice storms, snow, blizzard, hurricane, typhoons, tropical storms, and cold wet weather. A disaster..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms...

7 CFR 760.702 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms, ice storms, snow, blizzard, hurricane, typhoons, tropical storms, and cold wet weather. A disaster..., moisture, humidity, severe storms, thunderstorms, ground saturation or standing water, hail, winter storms...

Raising of Operating a Motor Vehicle Effects on Environment in Winter

NASA Astrophysics Data System (ADS)

Ertman, S. A.; Ertman, J. A.; Zakharov, D. A.

2016-08-01

Severe low-temperature conditions, in which considerable part of Russian Motor Park is operated, affect vehicles negatively. Cold weather causes higher fuel consumption and C02 emissions always. It is because of temperature profile changing of automobile motors, other systems and materials. For enhancement of car operation efficiency in severe winter environment the dependency of engine warm-up and cooling time on ambient air temperature and wind speed described by multifactorial mathematical models is established. -On the basis of experimental research it was proved that the coolant temperature constitutes the engine representative temperature and may be used as representative temperature of engine at large. The model of generation of integrated index for vehicle adaptability to winter operating conditions by temperature profile of engines was developed. the method for evaluation of vehicle adaptability to winter operating conditions by temperature profile of engines allows to decrease higher fuel consumption in cold climate.

Is the OJIP Test a Reliable Indicator of Winter Hardiness and Freezing Tolerance of Common Wheat and Triticale under Variable Winter Environments?

PubMed Central

Rapacz, Marcin; Sasal, Monika; Kalaji, Hazem M.; Kościelniak, Janusz

2015-01-01

OJIP analysis, which explores changes in photosystem II (PSII) photochemical performance, has been used as a measure of plant susceptibility to stress. However, in the case of freezing tolerance and winter hardiness, which are highly environmentally variable, the use of this method can give ambiguous results depending on the species as well as the sampling year and time. To clarify this issue, we performed chlorophyll fluorescence measurements over three subsequent winters (2010/11, 2011/12 and 2012/13) on 220 accessions of common winter wheat and 139 accessions of winter triticale. After freezing, leaves were collected from cold-acclimated plants in the laboratory and field-grown plants. Observations of field survival in seven locations across Poland and measurements of freezing tolerance of the studied plants were also recorded. Our results confirm that the OJIP test is a reliable indicator of winter hardiness and freezing tolerance of common wheat and triticale under unstable winter environments. Regardless of species, the testing conditions giving the most reliable results were identical, and the reliability of the test could be easily checked by analysis of some relationships between OJIP-test parameters. We also found that triticale is more winter hardy and freezing tolerant than wheat. In addition, the two species were characterized by different patterns of photosynthetic apparatus acclimation to cold. PMID:26230839

Is the OJIP Test a Reliable Indicator of Winter Hardiness and Freezing Tolerance of Common Wheat and Triticale under Variable Winter Environments?

PubMed

Rapacz, Marcin; Sasal, Monika; Kalaji, Hazem M; Kościelniak, Janusz

2015-01-01

OJIP analysis, which explores changes in photosystem II (PSII) photochemical performance, has been used as a measure of plant susceptibility to stress. However, in the case of freezing tolerance and winter hardiness, which are highly environmentally variable, the use of this method can give ambiguous results depending on the species as well as the sampling year and time. To clarify this issue, we performed chlorophyll fluorescence measurements over three subsequent winters (2010/11, 2011/12 and 2012/13) on 220 accessions of common winter wheat and 139 accessions of winter triticale. After freezing, leaves were collected from cold-acclimated plants in the laboratory and field-grown plants. Observations of field survival in seven locations across Poland and measurements of freezing tolerance of the studied plants were also recorded. Our results confirm that the OJIP test is a reliable indicator of winter hardiness and freezing tolerance of common wheat and triticale under unstable winter environments. Regardless of species, the testing conditions giving the most reliable results were identical, and the reliability of the test could be easily checked by analysis of some relationships between OJIP-test parameters. We also found that triticale is more winter hardy and freezing tolerant than wheat. In addition, the two species were characterized by different patterns of photosynthetic apparatus acclimation to cold.

Membrane stability of winter wheat plants exposed to subzero temperatures for variable lengths of time

USDA-ARS?s Scientific Manuscript database

The ability to survive episodes of subfreezing temperature is essential to winter wheat. Fully cold-acclimated plants of six lines of winter wheat were exposed to -12, -14, -16 or -18° C, four 1-5 hours. Electrolyte leakage and plant survival were used to assess damage to the plants. Plants exposed ...

Developmental arrest during embryonic development of the common chameleon (Chamaeleo chamaeleon) in Spain.

PubMed

Andrews, Robin M; Díaz-Paniagua, Carmen; Marco, Adolfo; Portheault, Alexandre

2008-01-01

Embryonic development of the common chameleon, Chamaeleo chamaeleon, was monitored from oviposition to hatching at a field site in southwestern Spain and in the laboratory under five experimental temperature regimes. Embryos were diapausing gastrulae at the time of oviposition; developmental arrest in the field continued as cold torpor during winter. Postarrest development in the field commenced in April, and hatching occurred in August, for a total incubation period of 10.5 mo. In the laboratory, one group of eggs was incubated at a constant warm (26 degrees C) temperature. The remaining treatments simulated field conditions and consisted of initial periods of warm temperature of 0, 27, 46, and 71 d, a subsequent 4-mo period of cold winter (16 degrees C) temperature, and a final period of warm (26 degrees C) temperature. Embryos in the constant warm temperature treatment were in diapause an average of 3 mo, with clutch means ranging from 2 to 4 mo. Hatching among clutches occurred over 2 mo. In contrast, for field and experimental eggs that experienced cold winter conditions, hatching within treatments occurred over 2-14 d; "winter" conditions synchronized development. The length of time between the end of cold conditions and hatching did not differ among treatments; development thus resumed as soon as temperature was suitable regardless of the initial period of warm temperature. Diapause in nature thus insures that embryos remain gastrulae after oviposition despite nest temperatures that may be warm enough to support development.

Cold-Specific Induction of a Dehydrin Gene Family Member in Barley.

PubMed Central

Van Zee, K.; Chen, F. Q.; Hayes, P. M.; Close, T. J.; Chen, THH.

1995-01-01

An interval on barley (Hordeum vulgare L.) chromosome 7 accounting for significant quantitative trait locus effects for winter hardiness were detected in a winter (Dicktoo) x spring (Morex) barley population (P.M. Hayes, T. Blake, T.H.H. Chen, S. Tragoonrung, F. Chen, A. Pan, and B. Liu [1993] Genome 36: 66-71). Two members of the barley dehydrin gene family, Dhn1 and Dhn2, were located within the region defining the winter hardiness quantitative trait locus effect (A. Pan, P.M. Hayes, F. Chen, T. Blake, T.H.H. Chen, T.T.S. Wright, I. Karsai, Z. Bedo [1994] Theor Appl Genet 89: 900-910). To investigate the possible role of Dhn1 and Dhn2 in winter hardiness, we examined the expression pattern of six barley dehydrin gene family members in shoot tissue in response to cold temperature. Incubation of 3-week-old barley plants at 2[deg]C resulted in a rapid induction of a single 86-kD polypeptide that was recognized by an antiserum against a peptide conserved in the dehydrin gene family. Northern blot analysis confirmed the induction of an mRNA corresponding to Dhn5. The expression patterns of cold-induced dehydrins in shoot tissue for Dicktoo and Morex were identical under the conditions studied, in spite of the known phenotypic differences in their winter hardiness. These results, together with the allelic structure of selected high- and low-survival lines, suggest that the Dicktoo alleles at the Dhn1 and Dhn2 may not be the primary determinants of winter hardiness in barley. PMID:12228540

2009/2010 Eurasian Cold Winter and Loss of Arctic Sea-ice over Barents/Kara Sea

NASA Astrophysics Data System (ADS)

Shim, T.; Kim, B.; Kim, S.

2012-12-01

In 2009/2010 winter, a few extreme cold events and heavy snowfall occurred over central North America, north western Europe, and East Asia exerting a severe social and economic impacts. In this study, we performed modeling experiments to examine the role of substantially reduced Arctic sea-ice over Barents/Kara Sea on the 2009/2010 cold winters. Although several previous studies investigated cause of the extreme events and emphasized the large snow-covered area over Siberia in autumn 2009, we note that the area extent of Arctic sea-ice over Barents/Kara sea in autumn 2009 was anomalously low and the possible impact from Arctic for the extreme cold events has not been presented. To investigate the influence from the Arctic, we designed three model runs using Community Atmosphere Model Version 3 (CAM3). Each simulation differs by the prescribed surface boundary conditions: (a) CTRL - climatological seasonal cycle of sea surface temperature (SST) and sea-ice concentration (SIC) are prescribed everywhere, (b) EXP_65N - SST and SIC inside the Arctic circle (north of 65°N) are replaced by 2009/2010 values. Elsewhere, the climatology is used, (c) EXP_BK - Same with (b) except that SIC and SST are fixed only over Barents/Kara Sea where the sea-ice area dropped significantly in 2009/2010 winter. Model results from EXP_65N and EXP_BK commonly showed a large increase of air temperature in the lower troposphere where Arctic sea-ice showed a large reduction. Also, compared with the observation, model successfully captured thickened geopotential height in the Arctic and showed downstream wave propagation toward midlatitude. From the analysis, we reveal that this large dipolar Arctic-midlatitude teleconnection pattern in the upper troposphere easily propagate upward and played a role in the weakening of polar vortex. This is also confirmed in the observation. However, the timing of excitation of upward propagating wave in EXP_65N and EXP_BK were different and thus the timing of weakening of polar vortex also differs in each experiment. Unlike with our expectation, both EXP_65N and EXP_BK did not capture the abrupt increase of snow-cover in the observation over Siberian region in autumn 2009. Therefore, given the successful reproduction of key observed features of cold winter 2009/2010 by EXP_65N and EXP_BK, we conclude that Arctic sea-ice in autumn 2009 played a key role for the subsequent development of cold winter 2009/2010 and the role was largely independent with the autumn snow-cover.

Snow cover and extreme winter warming events control flower abundance of some, but not all species in high arctic Svalbard

PubMed Central

Semenchuk, Philipp R; Elberling, Bo; Cooper, Elisabeth J

2013-01-01

Abstract The High Arctic winter is expected to be altered through ongoing and future climate change. Winter precipitation and snow depth are projected to increase and melt out dates change accordingly. Also, snow cover and depth will play an important role in protecting plant canopy from increasingly more frequent extreme winter warming events. Flower production of many Arctic plants is dependent on melt out timing, since season length determines resource availability for flower preformation. We erected snow fences to increase snow depth and shorten growing season, and counted flowers of six species over 5 years, during which we experienced two extreme winter warming events. Most species were resistant to snow cover increase, but two species reduced flower abundance due to shortened growing seasons. Cassiope tetragona responded strongly with fewer flowers in deep snow regimes during years without extreme events, while Stellaria crassipes responded partly. Snow pack thickness determined whether winter warming events had an effect on flower abundance of some species. Warming events clearly reduced flower abundance in shallow but not in deep snow regimes of Cassiope tetragona, but only marginally for Dryas octopetala. However, the affected species were resilient and individuals did not experience any long term effects. In the case of short or cold summers, a subset of species suffered reduced reproductive success, which may affect future plant composition through possible cascading competition effects. Extreme winter warming events were shown to expose the canopy to cold winter air. The following summer most of the overwintering flower buds could not produce flowers. Thus reproductive success is reduced if this occurs in subsequent years. We conclude that snow depth influences flower abundance by altering season length and by protecting or exposing flower buds to cold winter air, but most species studied are resistant to changes. Winter warming events, often occurring together with rain, can substantially remove snow cover and thereby expose plants to cold winter air. Depending on morphology, different parts of the plant can be directly exposed. On this picture, we see Dryas octopetala seed heads from the previous growing season protrude through the remaining ice layer after a warming event in early 2010. The rest of the plant, including meristems and flower primordia, are still somewhat protected by the ice. In the background we can see a patch of Cassiope tetragona protruding through the ice; in this case, the whole plant including flower primordia is exposed, which might be one reason why this species experienced a loss of flowers the following season. Photograph by Philipp Semenchuk. PMID:24567826

Evidence of lumpy skin disease virus over-wintering by transstadial persistence in Amblyomma hebraeum and transovarial persistence in Rhipicephalus decoloratus ticks.

PubMed

Lubinga, J C; Tuppurainen, E S M; Coetzer, J A W; Stoltsz, W H; Venter, E H

2014-01-01

Lumpy skin disease is a debilitating cattle disease caused by the lumpy skin disease virus (LSDV), belonging to the genus Capripoxvirus. Epidemics of the disease usually occur in summer, when insect activity is high. Limited information is available on how LSDV persists during inter-epidemic periods. Transmission of LSDV by mosquitoes such as Aedes aegypti has been shown to be mechanical, there is no carrier state in cattle and the role of wildlife in the epidemiology of the disease seems to be of minor importance. Recent studies in ticks have shown transstadial persistence of LSDV in Rhipicephalus appendiculatus and Amblyomma hebraeum as well as transovarial persistence of the virus in Rhipicephalus decoloratus, R. appendiculatus and A. hebraeum. The over-wintering of ticks off the host as part of their life cycles is well known: A. hebraeum and R. appendiculatus over-winter, for example, on the ground as engorged nymphs/unfed (emergent) adults while R. decoloratus over-winters on the ground as engorged females. In this study, transstadial and transovarial persistence of LSDV from experimentally infected A. hebraeum nymphs and R. decoloratus females after exposure to cold temperatures of 5 °C at night and 20 °C during the day for 2 months was reported. This observation suggests possible over-wintering of the virus in these tick species.

Recent climate hiatus revealed dual control by temperature and drought on the stem growth of Mediterranean Quercus ilex.

PubMed

Lempereur, Morine; Limousin, Jean-Marc; Guibal, Frédéric; Ourcival, Jean-Marc; Rambal, Serge; Ruffault, Julien; Mouillot, Florent

2017-01-01

A better understanding of stem growth phenology and its climate drivers would improve projections of the impact of climate change on forest productivity. Under a Mediterranean climate, tree growth is primarily limited by soil water availability during summer, but cold temperatures in winter also prevent tree growth in evergreen forests. In the widespread Mediterranean evergreen tree species Quercus ilex, the duration of stem growth has been shown to predict annual stem increment, and to be limited by winter temperatures on the one hand, and by the summer drought onset on the other hand. We tested how these climatic controls of Q. ilex growth varied with recent climate change by correlating a 40-year tree ring record and a 30-year annual diameter inventory against winter temperature, spring precipitation, and simulated growth duration. Our results showed that growth duration was the best predictor of annual tree growth. We predicted that recent climate changes have resulted in earlier growth onset (-10 days) due to winter warming and earlier growth cessation (-26 days) due to earlier drought onset. These climatic trends partly offset one another, as we observed no significant trend of change in tree growth between 1968 and 2008. A moving-window correlation analysis revealed that in the past, Q. ilex growth was only correlated with water availability, but that since the 2000s, growth suddenly became correlated with winter temperature in addition to spring drought. This change in the climate-growth correlations matches the start of the recent atmospheric warming pause also known as the 'climate hiatus'. The duration of growth of Q. ilex is thus shortened because winter warming has stopped compensating for increasing drought in the last decade. Decoupled trends in precipitation and temperature, a neglected aspect of climate change, might reduce forest productivity through phenological constraints and have more consequences than climate warming alone. © 2016 John Wiley & Sons Ltd.

Cold temperature increases winter fruit removal rate of a bird-dispersed shrub

Treesearch

Charles Kwit; Douglas J. Levey; Cathryn H. Greenberg; Scott F. Pearson; John P. McCarty; Sarah Sargent

2004-01-01

We tested the hypothesis that winter removal rates of fruits of wax myrtle, Myrica cerifera, are higher in colder winters. Over a 9-year period, we monitored M. cerifera fruit crops in 13 0.1-ha study plots in South Carolina, U.S.A. Peak ripeness occurred in November, whereas peak removal occurred in the coldest months, December...

Prediction of thermal behavior of pervious concrete pavements in winter.

DOT National Transportation Integrated Search

2017-05-15

Because application of pervious concrete pavement (PCPs) has extended to cold-climate regions of the United States, the safety and : mobility of PCP installations during the winter season need to be maintained. Timely application of salt, anti-icing,...

Is the wide distribution of aspen a result of its stress tolerance?

Treesearch

V. J. Lieffers; S. M. Landhausser; E. H. Hogg

2001-01-01

Populus tremuloides is distributed from drought-prone fringes of the Great Plains to extremely cold sites at arctic treeline. To occupy these conditions aspen appears to be more tolerant of stress than the other North American species of the genus Populus. Cold winters, cold soil conditions during the growing season, periodic drought, insect defoliation, and...

Local atmospheric decoupling in complex topography alters climate change impacts

Treesearch

Christopher Daly; David R. Conklin; Michael H. Unsworth

2009-01-01

Cold air drainage and pooling occur in many mountain valleys, especially at night and during winter. Local climate regimes associated with frequent cold air pooling have substantial impacts on species phenology, distribution, and diversity. However, little is known about how the degree and frequency of cold air drainage and pooling will respond to a changing climate....

Induction of DREB2A pathway with repression of E2F, Jasmonic acid biosynthetic and photosynthesis pathways in cold acclimation specific freeze resistant wheat crown

USDA-ARS?s Scientific Manuscript database

Winter wheat lines can achieve cold acclimation (development of tolerance to freezing temperatures) and vernalization (delay in transition from vegetative to reproductive phase) in response to low non-freezing temperatures. To describe cold acclimation specific processes and pathways, we utilized co...

Achoo! Cold, Flu, or Something Else? | NIH MedlinePlus the Magazine

MedlinePlus

... Flu, or Something Else? Follow us Achoo! Cold, Flu, or Something Else? Photo: iStock Winter and early ... over-the-counter medicines to ease symptoms. Seasonal Flu Symptoms usually last one to two weeks. Include ...

Research on the enhancement of biological nitrogen removal at low temperatures from ammonium-rich wastewater by the bio-electrocoagulation technology in lab-scale systems, pilot-scale systems and a full-scale industrial wastewater treatment plant.

PubMed

Li, Liang; Qian, Guangsheng; Ye, Linlin; Hu, Xiaomin; Yu, Xin; Lyu, Weijian

2018-09-01

In cold areas, nitrogen removal performance of wastewater treatment plants (WWTP) declines greatly in winter. This paper systematically describes the enhancement effect of a periodic reverse electrocoagulation technology on biological nitrogen removal at low temperatures. The study showed that in the lab-scale systems, the electrocoagulation technology improved the biomass amount, enzyme activity and the amount of nitrogen removal bacteria (Nitrosomonas, Nitrobacter, Paracoccus, Thauera and Enterobacter). This enhanced nitrification and denitrification of activated sludge at low temperatures. In the pilot-scale systems, the electrocoagulation technology increased the relative abundance of cold-adapted microorganisms (Luteimonas and Trueperaceae) at low temperatures. In a full-scale industrial WWTP, comparison of data from winter 2015 and winter 2016 showed that effluent chemical oxygen demand (COD), NH 4 + -N, and NO 3 - -N reduced by 10.37, 3.84, and 136.43 t, respectively, throughout the winter, after installation of electrocoagulation devices. These results suggest that the electrocoagulation technology is able to improve the performance of activated sludge under low-temperature conditions. This technology provides a new way for upgrading of the performance of WWTPs in cold areas. Copyright © 2018 Elsevier Ltd. All rights reserved.

[A survey of knowledge on common cold and its treatment situation among physicians from various levels of hospitals in mainland China].

PubMed

Su, Nan; Lin, Jiang-tao; Liu, Guan-jian; Lin, Yan-ping; Yin, Kai-sheng; Bai, Chun-xue; Ma, Li-jun; Qiu, Chen; Liu, Chun-tao; Chen, Ming-wei; Liu, Hua; Chen, Ping

2012-04-01

To investigate the cognition of the common cold and current situation of the treatment among physicians from various levels of hospitals in Chinese mainland, so as to provide evidence for future continuing medical education and rational medication. A questionnaire designed for this survey was used to learn about the general information, cognitive degree of the common cold and prescription habits of physician who prescribed for cold within last three months, from various levels hospitals. A total of 1001 physicians were interviewed. Among them, 749 physicians chose right options that the cold was the common cold and the influenza with 79.84% in resident physicians and 56.76% in chief physicians. A total of 745 physicians chose options that the course of common cold will be lasting 4 to 7 days; 895 physicians chose options that old people are the most susceptible for complication; 669 physicians thought the common cold was the most common infection in winter; 841 physicians used clinical methods to diagnose the common cold; 736 physicians thought although the cold was a kind of self-limited disease and symptomatic treatment could alleviate symptoms and improve life quality, patients should see doctor in time if it turns to severer; and 745 physicians held the opinion that treatment of the common cold should focus on relieving symptoms first. In addition, 61.60% physicians had made prescription based on clinical symptoms; 505 (54.24%) of them thought compound drugs were priority in treating the common cold. However, there were still 43 physicians prescribed antibiotics for common cold. There is misunderstanding and discrepancy in cognition towards common cold and treatment among physicians from various levels of hospitals in mainland China. Physicians should standardize diagnosis and treatment for the common cold according to the domestic and foreign guidelines.

Role of cold surge and MJO on rainfall enhancement over indonesia during east asian winter monsoon

NASA Astrophysics Data System (ADS)

Fauzi, R. R.; Hidayat, R.

2018-05-01

Intensity of precipitation in Indonesia is influenced by convection and propagation of southwest wind. Objective of this study is to analyze the relationship between cold surge and the phenomenon of intra-seasonal climate variability Madden-julian Oscillation (MJO) for affecting precipitation in Indonesia. The data used for identifying the occurrence of cold surge are meridional wind speed data from the ERA-Interim. In addition, this study also used RMM1 and RMM2 index data from Bureau of Meteorology (BOM) for identifying MJO events. The results showed that during East Asian Winter Monsoon (EAWM) in 15 years (2000-2015), there are 362 cold surge events, 186 MJO events, and 113 cold surge events were associated with MJO events. The spread of cold surge can penetrate to equator and brought mass of water vapor that causes dominant precipitation in the Indonesian Sea up to 50-75% from climatological precipitation during EAWM. The MJO convection activity that moves from west to east also increases precipitation, but the distribution of rainfall is wider than cold surge, especially in Eastern Indonesia. MJO and cold surge simultaneously can increase rainfall over 100-150% in any Indonesian region that affected by MJO and cold surge events. The mechanism of heavy rainfall is illustrated by high activity of moisture transport in areas such as Java Sea and coastal areas of Indonesia.

Extremely cold events and sudden air temperature drops during winter season in the Czech Republic

NASA Astrophysics Data System (ADS)

Crhová, Lenka; Valeriánová, Anna; Holtanová, Eva; Müller, Miloslav; Kašpar, Marek; Stříž, Martin

2014-05-01

Today a great attention is turned to analysis of extreme weather events and frequency of their occurrence under changing climate. In most cases, these studies are focused on extremely warm events in summer season. However, extremely low values of air temperature during winter can have serious impacts on many sectors as well (e.g. power engineering, transportation, industry, agriculture, human health). Therefore, in present contribution we focus on extremely and abnormally cold air temperature events in winter season in the Czech Republic. Besides the seasonal extremes of minimum air temperature determined from station data, the standardized data with removed annual cycle are used as well. Distribution of extremely cold events over the season and the temporal evolution of frequency of occurrence during the period 1961-2010 are analyzed. Furthermore, the connection of cold events with extreme sudden temperature drops is studied. The extreme air temperature events and events of extreme sudden temperature drop are assessed using the Weather Extremity Index, which evaluates the extremity (based on return periods) and spatial extent of the meteorological extreme event of interest. The generalized extreme value distribution parameters are used to estimate return periods of daily temperature values. The work has been supported by the grant P209/11/1990 funded by the Czech Science Foundation.

Deficit irrigation strategies and wine grape cold hardiness

USDA-ARS?s Scientific Manuscript database

Winter survival of winegrapes grown at northern latitudes depends upon the ability of dormant tissue to withstand low temperature exposure and acclimate to winter temperature fluctuations. Deficit irrigation is used extensively in arid wine grape production regions to manage growth for improved grap...

Long-term variability of dust events in Iceland (1949-2011)

NASA Astrophysics Data System (ADS)

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.

2014-06-01

Long-term frequency of atmospheric dust observations was investigated for the southern part of Iceland and merged with results obtained from the Northeast Iceland (Dagsson-Waldhauserova et al., 2013). In total, over 34 dust days per year on average occurred in Iceland based on conventionally used synoptic codes for dust. Including codes 04-06 into the criteria for dust observations, the frequency was 135 dust days annually. The Sea Level Pressure (SLP) oscillation controlled whether dust events occurred in NE (16.4 dust days annually) or in southern part of Iceland (about 18 dust days annually). The most dust-frequent decade in S Iceland was the 1960s while the most frequent decade in NE Iceland was the 2000s. A total of 32 severe dust storms (visibility < 500 m) was observed in Iceland with the highest frequency during the 2000s in S Iceland. The Arctic dust events (NE Iceland) were typically warm and during summer/autumn (May-September) while the Sub-Arctic dust events (S Iceland) were mainly cold and during winter/spring (March-May). About half of dust events in S Iceland occurred in winter or at sub-zero temperatures. A good correlation was found between PM10 concentrations and visibility during dust observations at the stations Vik and Storhofdi. This study shows that Iceland is among the dustiest areas of the world and dust is emitted the year-round.

Aircraft NOx and O3 measurements during wintertime temperature inversions in Salt Lake City, Utah

NASA Astrophysics Data System (ADS)

Womack, C.; Fibiger, D. L.; McDuffie, E. E.; Franchin, A.; Goldberger, L.; Moravek, A.; Middlebrook, A. M.; Thornton, J. A.; Murphy, J. G.; Baasandorj, M.; Brown, S. S.

2017-12-01

The topography of northern Utah results in several multi-day persistent cold-air pools (PCAPs) each winter, during which a temperature inversion prevents the mix-out of anthropogenic emissions. Pollutant levels rise over the course of several days, resulting in particulate matter (PM2.5) levels exceeding the US National Ambient Air Quality Standard of 35 µg/m3, often reaching 60-70 µg/m3 or higher. However, there is significant variability within individual valleys, whose emissions are predominately urban (as in Salt Lake City Valley), agricultural (as in Cache Valley), or a combination of the two. The Utah Winter Fine Particulate Matter Study (UWFPS 2017) was a ground- and aircraft-based field campaign that took place in Jan-Feb 2017 with the aim of better characterizing the complex chemistry involved in the buildup of PM2.5. On board the NOAA Twin Otter aircraft was a cavity ringdown instrument for measuring nitrogen oxides and ozone, an I- CIMS for gas phase oxidized reactive nitrogen, an AMS that measured particulate phase nitrate, and a mid-infrared absorption instrument for NH3. We report vertical and horizontal distributions of NOx, NOy, and O3, and their variation with meteorological conditions and time of day, in the urban and rural valleys of northern Utah.

High Time Resolution Measurements of VOCs from Vehicle Cold Starts: The Air Toxic Cold Start Pulse

NASA Astrophysics Data System (ADS)

Jobson, B. T.; Huangfu, Y.; Vanderschelden, G. S.

2017-12-01

Pollutants emitted during motor vehicle cold starts, especially in winter in some climates, is a significant source of winter time air pollution. While data exist for CO, NO, and total hydrocarbon emissions from federal testing procedures for vehicle emission certification, little is known about the emission rates of individual volatile organic compounds, in particular the air toxics benzene, formaldehyde, and acetaldehyde. Little is known about the VOC speciation and temperature dependence for cold starts. The US EPA vehicle emission model MOVES assumes that cold start emissions have the same speciation profile as running emissions. We examined this assumption by measuring cold start exhaust composition for 4 vehicles fueled with E10 gasoline over a temperature range of -4°C to 10°C in winter of 2015. The extra cold start emissions were determined by comparison with emissions during engine idling. In addition to CO and NOx measurements a proton transfer reaction mass spectrometer was used to measure formaldehyde, acetaldehyde, benzene, toluene, and C2-alkylbenzenes at high time resolution to compare with the cold start emission speciation profiles used in the EPA MOVES2014 model. The results show that after the vehicle was started, CO mixing ratios can reach a few percent of the exhaust and then drop to several ppmv within 2 minutes of idling, while NOx showed different temporal behaviors among the four vehicles. VOCs displayed elevated levels during cold start and the peak mixing ratios can be two orders higher than idling phase levels. Molar emission ratios relative to toluene were used to compare with the emission ratio used in MOVES2014 and we found the formaldehyde-to-toluene emission ratio was about 0.19, which is 5 times higher than the emission ratio used in MOVES2014 and the acetaldehyde-to-toluene emission ratios were 0.86-0.89, which is 8 times higher than the ones in MOVES2014. The C2-alkylbenzene-to-toluene ratio agreed well with moves. Our results suggest that for the air toxics acetaldehyde and formaldehyde, wintertime cold temperature vehicle start emissions are likely significantly underestimated in the MOVES 2014 model.

Comparison of the Impact of the Arctic Oscillation and East Atlantic - West Russia Teleconnection on Interannual Variation in East Asian Winter Temperatures and Monsoon

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Kim, Hae-Dong

2014-01-01

The large-scale impacts of the Arctic Oscillation (AO) and the East Atlantic/West Russia (EA/WR) teleconnection on the East Asian winter climate anomalies are compared for the past 34 winters focusing on 1) interannual monthly to seasonal temperature variability, 2) East Asian winter monsoon (EAWM), and 3) the Siberian high (SH) and cold surge. Regression analysis reveals warming by AO and EA/WR over mid-latitude East Asia during their positive phase and vice versa. The EA/WR impact is found to be comparable to the AO impact in affecting the East Asian temperature and monsoon. For example, warm (cold) months over mid-latitude East Asia during the positive (negative) AO are clearly seen when the AO and EA/WR are in the same phase. Near zero correlation is found between temperature and the AO phase when both teleconnections are in an opposite phase. The well-known negative relationship between SH and the AO phase is observed significantly more often when the AO is in the same phase with the EA/WR. Also, the indices of EAWM, cold surge, and SH are found to be more highly negative-correlated with the EA/WR rather than with the AO. The advective temperature change and associated circulation demonstrate that the anomalous large-scale field including the SH over the mid-latitude Asian inland is better represented by the EA/WR, influencing the East Asian winter climates. These results suggest that the impact of EA/WR should be considered more important than previously thought for a better understanding of East Asian winter temperature and monsoon variability.

Cold Tolerance of Mountain Pine Beetle (Coleoptera: Curculionidae) Eggs From the Historic and Expanded Ranges.

PubMed

Bleiker, K P; Smith, G D; Humble, L M

2017-10-01

Winter mortality is expected to be a key factor determining the ability of mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), to expand its range in Canada. We determined the mortality rate and supercooling points of eggs from the beetle's historic range in southern British Columbia as well as the recently expanded range in north-central Alberta and tested if eggs require an extended period of chilling to reach their maximum cold tolerance. We found no effect of population source or acclimation time on egg cold tolerance. Although 50% of eggs can survive brief exposure to -20.5 °C (LT50), storage at 0.3 °C and -7.5 °C for 59 d resulted in 50% and 100% mortality, respectively. Our results indicate that eggs suffer significant prefreeze mortality and are not well-adapted to overwintering: eggs are unlikely to survive winter throughout much of the beetle's range. Our results provide information that can be used to help model the climatic suitability of mountain pine beetle, including how changes in seasonality associated with new or changing climates may affect winter survival. In addition to lower lethal temperatures, it is critical that the duration of exposure to sublethal cold temperatures are considered in a comprehensive index of cold tolerance and incorporated into survival and population models. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Dense Winter Water Mass Formation In The Northwestern Pacific Marginal Seas:

NASA Astrophysics Data System (ADS)

Talley, L.; Lobanov, V.; Tishchenko, P.; Shcherbina, A.; Rudnick, D.; Salyuk, A.; Sagalaev, S.; Ponomarev, V.; Zhabin, I.

Two separate winter water mass formation experiments were carried out in the north- western Pacific. The Japan/East Sea (JES) is well-ventilated to the bottom (3500 m depth), and is much better ventilated than the adjacent North Pacific at the same depth and density. Winter data from 1999 and 2000 show that the JES is one of the few sites in the world with deep winter convection, and that convection in the JES has many similarities to convection in the Mediterranean. It was shown previously that deep oxygen in the JES has been declining over many decades, suggesting that ventilation was more vigorous early in the 20th century than in recent decades. Nevertheless, the presence of significant oxygen and chlorofluorocarbons to the JES bottom suggests ongoing ventilation. In winter, 1999, a first late-winter survey of the northern JES included one hydrographic station with evidence of open-ocean convection to about 1100 meters in the cold air outbreak region south of Vladivostok, and weak evidence of brine rejection under ice formation in Peter the Great Bay (shelf near Vladivos- tok). Topography and the presence of a semi-permanent anticyclonic eddy and the subpolar front delineate the convection region, which is in the path of strong northerly winter winds. Persistently colder conditions in winter 2000, including Vladivostok air temperatures colder than any other year since 1976 and SST -2C below normal in the northern Japan Sea, showed widespread convection. Significant bottom water was created through brine rejection in Peter the Great Bay and was found the base of the continental slope south of Vladivostok. Ventilation of North Pacific Intermediate Water occurs in the Okhotsk Sea, through brine rejection during sea ice formation, in polynyas on the northwest shelf. Moored observations on the shelf during winter 1999-2000 showed the creation of dense shelf water at 26.95 sigma_theta and clear evidence of brine rejection through the winter. The 1999 deployment hydrographic survey shows cold, dense water from the shelf at 26.95 sigma_theta. The lower density shelf water in June 2000 compared with Septem- ber 1999 is consistent with the reduced severity of winter 2000. Outflow of the densest cold water of shelf origin in both the 1999 and 2000 CTD surveys was located slightly inshore of the axis of the deepest channel between Sakhalin and Kashevarov Bank.

Calcium addition at the Hubbard Brook Experimental Forest reduced winter injury to red spruce in a high-injury year

Treesearch

Gary J. Hawley; Paul G. Schaberg; Christopher Eagar; Catherine H. Borer

2006-01-01

Laboratory experiments have verified that acid-deposition-induced calcium (Ca) leaching reduces the foliar cold tolerance of red spruce (Picea rubens Sarg.) current-year foliage, increasing the risk of winter injury and crown deterioration. However, to date no studies have shown that ambient losses in soil Ca have resulted in increased winter injury...

Seasonal cues induce phenotypic plasticity of Drosophila suzukii to enhance winter survival.

PubMed

Shearer, Peter W; West, Jessica D; Walton, Vaughn M; Brown, Preston H; Svetec, Nicolas; Chiu, Joanna C

2016-03-22

As global climate change and exponential human population growth intensifies pressure on agricultural systems, the need to effectively manage invasive insect pests is becoming increasingly important to global food security. Drosophila suzukii is an invasive pest that drastically expanded its global range in a very short time since 2008, spreading to most areas in North America and many countries in Europe and South America. Preliminary ecological modeling predicted a more restricted distribution and, for this reason, the invasion of D. suzukii to northern temperate regions is especially unexpected. Investigating D. suzukii phenology and seasonal adaptations can lead to a better understanding of the mechanisms through which insects express phenotypic plasticity, which likely enables invasive species to successfully colonize a wide range of environments. We describe seasonal phenotypic plasticity in field populations of D. suzukii. Specifically, we observed a trend of higher proportions of flies with the winter morph phenotype, characterized by darker pigmentation and longer wing length, as summer progresses to winter. A laboratory-simulated winter photoperiod and temperature (12:12 L:D and 10 °C) were sufficient to induce the winter morph phenotype in D. suzukii. This winter morph is associated with increased survival at 1 °C when compared to the summer morph, thus explaining the ability of D. suzukii to survive cold winters. We then used RNA sequencing to identify gene expression differences underlying seasonal differences in D. suzukii physiology. Winter morph gene expression is consistent with known mechanisms of cold-hardening such as adjustments to ion transport and up-regulation of carbohydrate metabolism. In addition, transcripts involved in oogenesis and DNA replication were down-regulated in the winter morph, providing the first molecular evidence of a reproductive diapause in D. suzukii. To date, D. suzukii cold resistance studies suggest that this species cannot overwinter in northern locations, e.g. Canada, even though they are established pests in these regions. Combining physiological investigations with RNA sequencing, we present potential mechanisms by which D. suzukii can overwinter in these regions. This work may contribute to more accurate population models that incorporate seasonal variation in physiological parameters, leading to development of better management strategies.

Attribution of UK Winter Floods to Anthropogenic Forcing

NASA Astrophysics Data System (ADS)

Schaller, N.; Alison, K.; Sparrow, S. N.; Otto, F. E. L.; Massey, N.; Vautard, R.; Yiou, P.; van Oldenborgh, G. J.; van Haren, R.; Lamb, R.; Huntingford, C.; Crooks, S.; Legg, T.; Weisheimer, A.; Bowery, A.; Miller, J.; Jones, R.; Stott, P.; Allen, M. R.

2014-12-01

Many regions of southern UK experienced severe flooding during the 2013/2014 winter. Simultaneously, large areas in the USA and Canada were struck by prolonged cold weather. At the time, the media and public asked whether the general rainy conditions over northern Europe and the cold weather over North America were caused by climate change. Providing an answer to this question is not trivial, but recent studies show that probabilistic event attribution is feasible. Using the citizen science project weather@home, we ran over 40'000 perturbed initial condition simulations of the 2013/2014 winter. These simulations fall into two categories: one set aims at simulating the world with climate change using observed sea surface temperatures while the second set is run with sea surface temperatures corresponding to a world that might have been without climate change. The relevant modelled variables are then downscaled by a hydrological model to obtain river flows. First results show that anthropogenic climate change led to a small but significant increase in the fractional attributable risk for 30-days peak flows for the river Thames. A single number can summarize the final result from probabilistic attribution studies indicating, for example, an increase, decrease or no change to the risk of the event occurring. However, communicating this to the public, media and other scientists remains challenging. The assumptions made in the chain of models used need to be explained. In addition, extreme events, like the UK floods of the 2013/2014 winter, are usually caused by a range of factors. While heavy precipitation events can be caused by dynamic and/or thermodynamic processes, floods occur only partly as a response to heavy precipitation. Depending on the catchment, they can be largely due to soil properties and conditions of the previous months. Probabilistic attribution studies are multidisciplinary and therefore all aspects need to be communicated properly.

Cold Fronts in RegCM/HadGEM simulations over South America

NASA Astrophysics Data System (ADS)

Pampuch, Luana; Marcos de Jesus, Eduardo; Porfírio da Rocha, Rosmeri; Ambrizzi, Tércio

2017-04-01

Cold front is one of the most important systems that contribute for precipitation over South America. The representation of this system in climate models is important for a better representation of the precipitation. The Regional Climate Model RegCM is widely used for climate studies in South America, being important to understand how this model represents the cold fronts. A climatology (from 1979-2004) of the number of cold fronts in each season for RegCM4 simulations over South America CORDEX domain nested in HadGEM2-ES. The simulated climatology was compared with ERA-Interim reanalysis cold fronts climatology over the South America and adjacent South Atlantic Ocean. The cold fronts tracking for the model and the reanalysis were performed using an objective methodology based on decrease of air temperature in 925hPa, shift of meridional wind in 925hPa from northern to southern quadrant and increased in sea level pressure. The main differences were observed on summer and winter. On summer the model overestimate the number of cold fronts over southeastern South America and adjacent Atlantic Ocean; and underestimate it over central-south Argentina and Atlantic Ocean. On winter, the signs were opposite of that summer. On autumn and spring the differences were smaller and occurs mainly over all South Atlantic and north Argentina.

Winter storms drive rapid phenotypic, regulatory, and genomic shifts in the green anole lizard.

PubMed

Campbell-Staton, Shane C; Cheviron, Zachary A; Rochette, Nicholas; Catchen, Julian; Losos, Jonathan B; Edwards, Scott V

2017-08-04

Extreme environmental perturbations offer opportunities to observe the effects of natural selection in wild populations. During the winter of 2013-2014, the southeastern United States endured an extreme cold event. We used thermal performance, transcriptomics, and genome scans to measure responses of lizard populations to storm-induced selection. We found significant increases in cold tolerance at the species' southern limit. Gene expression in southern survivors shifted toward patterns characteristic of northern populations. Comparing samples before and after the extreme winter, 14 genomic regions were differentiated in the surviving southern population; four also exhibited signatures of local adaptation across the latitudinal gradient and implicate genes involved in nervous system function. Together, our results suggest that extreme winter events can rapidly produce strong selection on natural populations at multiple biological levels that recapitulate geographic patterns of local adaptation. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Development of a model system to identify differences in spring and winter oat.

PubMed

Chawade, Aakash; Lindén, Pernilla; Bräutigam, Marcus; Jonsson, Rickard; Jonsson, Anders; Moritz, Thomas; Olsson, Olof

2012-01-01

Our long-term goal is to develop a Swedish winter oat (Avena sativa). To identify molecular differences that correlate with winter hardiness, a winter oat model comprising of both non-hardy spring lines and winter hardy lines is needed. To achieve this, we selected 294 oat breeding lines, originating from various Russian, German, and American winter oat breeding programs and tested them in the field in south- and western Sweden. By assaying for winter survival and agricultural properties during four consecutive seasons, we identified 14 breeding lines of different origins that not only survived the winter but also were agronomically better than the rest. Laboratory tests including electrolytic leakage, controlled crown freezing assay, expression analysis of the AsVrn1 gene and monitoring of flowering time suggested that the American lines had the highest freezing tolerance, although the German lines performed better in the field. Finally, six lines constituting the two most freezing tolerant lines, two intermediate lines and two spring cultivars were chosen to build a winter oat model system. Metabolic profiling of non-acclimated and cold acclimated leaf tissue samples isolated from the six selected lines revealed differential expression patterns of 245 metabolites including several sugars, amino acids, organic acids and 181 hitherto unknown metabolites. The expression patterns of 107 metabolites showed significant interactions with either a cultivar or a time-point. Further identification, characterisation and validation of these metabolites will lead to an increased understanding of the cold acclimation process in oats. Furthermore, by using the winter oat model system, differential sequencing of crown mRNA populations would lead to identification of various biomarkers to facilitate winter oat breeding.

Subcellular distribution of raffinose oligosaccharides and other metabolites in summer and winter leaves of Ajuga reptans (Lamiaceae).

PubMed

Findling, Sarah; Zanger, Klaus; Krueger, Stephan; Lohaus, Gertrud

2015-01-01

In Ajuga reptans, raffinose oligosaccharides accumulated during winter. Stachyose, verbascose, and higher RFO oligomers were exclusively found in the vacuole whereas one-fourth of raffinose was localized in the stroma. The evergreen labiate Ajuga reptans L. can grow at low temperature. The carbohydrate metabolism changes during the cold phase, e.g., raffinose family oligosaccharides (RFOs) accumulate. Additionally, A. reptans translocates RFOs in the phloem. In the present study, subcellular concentrations of metabolites were studied in summer and winter leaves of A. reptans to gain further insight into regulatory instances involved in the cold acclimation process and into the function of RFOs. Subcellular metabolite concentrations were determined by non-aqueous fractionation. Volumes of the subcellular compartments of summer and winter leaves were analyzed by morphometric measurements. The metabolite content varied strongly between summer and winter leaves. Soluble metabolites increased up to tenfold during winter whereas the starch content was decreased. In winter leaves, the subcellular distribution showed a shift of carbohydrates from cytoplasm to vacuole and chloroplast. Despite this, the metabolite concentration was higher in all compartments in winter leaves compared to summer leaves because of the much higher total metabolite content in winter leaves. The different oligosaccharides did show different compartmentations. Stachyose, verbascose, and higher RFO oligomers were almost exclusively found in the vacuole whereas one-fourth of raffinose was localized in the stroma. Apparently, the subcellular distribution of the RFOs differs because they fulfill different functions in plant metabolism during winter. Raffinose might function in protecting chloroplast membranes during freezing, whereas higher RFO oligomers may exert protective effects on vacuolar membranes. In addition, the high content of RFOs in winter leaves may also result from reduced consumption of assimilates.

The winter gap effect in methane leak detection and repair with optical gas imaging cameras

NASA Astrophysics Data System (ADS)

Fox, T. A.; Barchyn, T.; Hugenholtz, C.

2017-12-01

Implementing effective leak detection and repair (LDAR) programs is essential for mitigating fugitive methane emissions from oil and gas operations. In Canada, newly proposed regulations will require that high-risk facilities be surveyed 3 times/yr for fugitive leaks. Like the United States, Canada promotes the use of Optical Gas Imaging cameras (OGIs) for detecting natural gas leaks during LDAR surveys. However, recent research suggests OGIs may perform poorly under adverse environmental conditions, especially in low temperatures. For regions like Canada that experience cold winters, OGIs may not be reliably used for months at a time, meaning that leaks may accumulate and emit for longer periods before being repaired. While considerable oil and gas activity occurs in high-latitude regions with cold winters, no research has explored how extended cold periods impact OGI-focused LDAR programs. To improve this understanding, we present a simple model exploring relationships among winter gap length, fugitive methane emissions, and investment input for LDAR programs employing OGI instruments in gas producing regions of different latitudes. Preliminary results suggest that longer gaps between LDAR surveys caused by cold temperatures result in either 1) higher total emissions for the year, or 2) greater time and equipment investment in LDAR programs to achieve emissions mitigation equivalent to LDAR programs operating under ideal conditions. When weather constraints are removed and LDAR surveys are evenly spaced throughout the year, emissions mitigation is optimized. However, as the winter gap duration and the size of the implicated area increases, fugitive leaks last longer. Furthermore, a spillover effect is observed as LDAR crews become overwhelmed with the high volume of work required as temperatures increase in the spring. Our model adds weight to the argument that LDAR programs should be tailored to regional needs, and that regulators should be more cognisant of sensor-specific limitations as they develop LDAR protocols.

Operational forecasting of daily temperatures in the Valencia Region. Part II: minimum temperatures in winter.

NASA Astrophysics Data System (ADS)

Gómez, I.; Estrela, M.

2009-09-01

Extreme temperature events have a great impact on human society. Knowledge of minimum temperatures during winter is very useful for both the general public and organisations whose workers have to operate in the open, e.g. railways, roadways, tourism, etc. Moreover, winter minimum temperatures are considered a parameter of interest and concern since persistent cold-waves can affect areas as diverse as public health, energy consumption, etc. Thus, an accurate forecasting of these temperatures could help to predict cold-wave conditions and permit the implementation of strategies aimed at minimizing the negative effects that low temperatures have on human health. The aim of this work is to evaluate the skill of the RAMS model in determining daily minimum temperatures during winter over the Valencia Region. For this, we have used the real-time configuration of this model currently running at the CEAM Foundation. To carry out the model verification process, we have analysed not only the global behaviour of the model for the whole Valencia Region, but also its behaviour for the individual stations distributed within this area. The study has been performed for the winter forecast period from 1 December 2007 - 31 March 2008. The results obtained are encouraging and indicate a good agreement between the observed and simulated minimum temperatures. Moreover, the model captures quite well the temperatures in the extreme cold episodes. Acknowledgement. This work was supported by "GRACCIE" (CSD2007-00067, Programa Consolider-Ingenio 2010), by the Spanish Ministerio de Educación y Ciencia, contract number CGL2005-03386/CLI, and by the Regional Government of Valencia Conselleria de Sanitat, contract "Simulación de las olas de calor e invasiones de frío y su regionalización en la Comunidad Valenciana" ("Heat wave and cold invasion simulation and their regionalization at Valencia Region"). The CEAM Foundation is supported by the Generalitat Valenciana and BANCAIXA (Valencia, Spain).

Copy number and haplotype variation at the VRN-A1 and central FR-A2 loci are associated with frost tolerance in hexaploid wheat.

PubMed

Zhu, Jie; Pearce, Stephen; Burke, Adrienne; See, Deven Robert; Skinner, Daniel Z; Dubcovsky, Jorge; Garland-Campbell, Kimberly

2014-05-01

The interaction between VRN - A1 and FR - A2 largely affect the frost tolerance of hexaploid wheat. Frost tolerance is critical for wheat survival during cold winters. Natural variation for this trait is mainly associated with allelic differences at the VERNALIZATION 1 (VRN1) and FROST RESISTANCE 2 (FR2) loci. VRN1 regulates the transition between vegetative and reproductive stages and FR2, a locus including several tandemly duplicated C-REPEAT BINDING FACTOR (CBF) transcription factors, regulates the expression of Cold-regulated genes. We identified sequence and copy number variation at these two loci among winter and spring wheat varieties and characterized their association with frost tolerance. We identified two FR-A2 haplotypes-'FR-A2-S' and 'FR-A2-T'-distinguished by two insertion/deletions and ten single nucleotide polymorphisms within the CBF-A12 and CBF-A15 genes. Increased copy number of CBF-A14 was frequently associated with the FR-A2-T haplotype and with higher CBF14 transcript levels in response to cold. Factorial ANOVAs revealed significant interactions between VRN1 and FR-A2 for frost tolerance in both winter and spring panels suggesting a crosstalk between vernalization and cold acclimation pathways. The model including these two loci and their interaction explained 32.0 and 20.7 % of the variation in frost tolerance in the winter and spring panels, respectively. The interaction was validated in a winter wheat F 4:5 population segregating for both genes. Increased VRN-A1 copy number was associated with improved frost tolerance among varieties carrying the FR-A2-T allele but not among those carrying the FR-A2-S allele. These results suggest that selection of varieties carrying the FR-A2-T allele and three copies of the recessive vrn-A1 allele would be a good strategy to improve frost tolerance in wheat.

Event attribution: Human influence on the record-breaking cold event in January of 2016 in Eastern China

NASA Astrophysics Data System (ADS)

Qian, C.; Wang, J.; Dong, S.; Yin, H.; Burke, C.; Ciavarella, A.; Dong, B.; Freychet, N.; Lott, F. C.; Tett, S. F.

2017-12-01

It is controversial whether Asian mid-latitude cold surges are becoming more likely as a consequence of Arctic warming. Here, we present an event attribution study in mid-latitude Eastern China. A strong cold surge occurred during 21st-25th January 2016 affecting most areas of China, especially Eastern China. Daily minimum temperature (Tmin) records were broken at many stations. The area averaged anomaly of Tmin over the region (20-44N, 100-124E) for this pentad was the lowest temperature recorded since modern meteorological observations started in 1960. This cold event occurred in a background of the warmest winter Tmin since 1960. Given the vast damages caused by this extreme cold event in Eastern China and the previous mentioned controversy, it is compelling to investigate how much anthropogenic forcing agents have affected the probability of cold events with an intensity equal to or larger than the January 2016 extreme event. We use the Met Office Hadley Centre system for Attribution of extreme weather and Climate Events and station observations to investigate the effect of anthropogenic forcings on the likelihood of such a cold event. Anthropogenic influences are estimated to have reduced the likelihood of an extreme cold event in mid-winter with the intensity equal to or stronger than the record of 2016 in Eastern China by about 2/3.

Role of CBFs as Integrators of Chloroplast Redox, Phytochrome and Plant Hormone Signaling during Cold Acclimation

PubMed Central

Kurepin, Leonid V.; Dahal, Keshav P.; Savitch, Leonid V.; Singh, Jas; Bode, Rainer; Ivanov, Alexander G.; Hurry, Vaughan; Hüner, Norman P. A.

2013-01-01

Cold acclimation of winter cereals and other winter hardy species is a prerequisite to increase subsequent freezing tolerance. Low temperatures upregulate the expression of C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB1) which in turn induce the expression of COLD-REGULATED (COR) genes. We summarize evidence which indicates that the integration of these interactions is responsible for the dwarf phenotype and enhanced photosynthetic performance associated with cold-acclimated and CBF-overexpressing plants. Plants overexpressing CBFs but grown at warm temperatures mimic the cold-tolerant, dwarf, compact phenotype; increased photosynthetic performance; and biomass accumulation typically associated with cold-acclimated plants. In this review, we propose a model whereby the cold acclimation signal is perceived by plants through an integration of low temperature and changes in light intensity, as well as changes in light quality. Such integration leads to the activation of the CBF-regulon and subsequent upregulation of COR gene and GA 2-oxidase (GA2ox) expression which results in a dwarf phenotype coupled with increased freezing tolerance and enhanced photosynthetic performance. We conclude that, due to their photoautotrophic nature, plants do not rely on a single low temperature sensor, but integrate changes in light intensity, light quality, and membrane viscosity in order to establish the cold-acclimated state. CBFs appear to act as master regulators of these interconnecting sensing/signaling pathways. PMID:23778089

Assessing the thermal dissipation sap flux density method for monitoring cold season water transport in seasonally snow-covered forests

DOE PAGES

Chan, Allison M.; Bowling, David R.

2017-05-26

Productivity of conifers in seasonally snow-covered forests is high before and during snowmelt when environmental conditions are optimal for photosynthesis. Climate change is altering the timing of spring in many locations, and changes in the date of transition from winter dormancy can have large impacts on annual productivity. Sap flow methods provide a promising approach to monitor tree activity during the cold season and the winter–spring and fall–winter transitions. Although sap flow techniques have been widely used, cold season results are generally not reported. Here we examine the feasibility of using the Granier thermal dissipation (TD) sap flux density methodmore » to monitor transpiration and dormancy of evergreen conifers during the cold season. We conducted a laboratory experiment which demonstrated that the TD method reliably detects xylem water transport (when it occurs) both at near freezing temperature and at low flow rate, and that the sensors can withstand repeated freeze–thaw events. However, the dependence between sensor output and water transport rate in these experiments differed from the established TD relation. In field experiments, sensors installed in two Abies forests lasted through two winters and a summer with low failure. The baseline (no-flow) sensor output varied considerably with temperature during the cold season, and a new baseline algorithm was developed to accommodate this variation. The Abies forests differed in elevation (2070 and 2620 m), and there was a clear difference in timing of initiation and cessation of transpiration between them. We conclude that the TD method can be reliably used to examine water transport during cold periods with associated low flow conditions« less

Assessing the thermal dissipation sap flux density method for monitoring cold season water transport in seasonally snow-covered forests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Allison M.; Bowling, David R.

Productivity of conifers in seasonally snow-covered forests is high before and during snowmelt when environmental conditions are optimal for photosynthesis. Climate change is altering the timing of spring in many locations, and changes in the date of transition from winter dormancy can have large impacts on annual productivity. Sap flow methods provide a promising approach to monitor tree activity during the cold season and the winter–spring and fall–winter transitions. Although sap flow techniques have been widely used, cold season results are generally not reported. Here we examine the feasibility of using the Granier thermal dissipation (TD) sap flux density methodmore » to monitor transpiration and dormancy of evergreen conifers during the cold season. We conducted a laboratory experiment which demonstrated that the TD method reliably detects xylem water transport (when it occurs) both at near freezing temperature and at low flow rate, and that the sensors can withstand repeated freeze–thaw events. However, the dependence between sensor output and water transport rate in these experiments differed from the established TD relation. In field experiments, sensors installed in two Abies forests lasted through two winters and a summer with low failure. The baseline (no-flow) sensor output varied considerably with temperature during the cold season, and a new baseline algorithm was developed to accommodate this variation. The Abies forests differed in elevation (2070 and 2620 m), and there was a clear difference in timing of initiation and cessation of transpiration between them. We conclude that the TD method can be reliably used to examine water transport during cold periods with associated low flow conditions« less

Responses of Picea mariana to elevated CO2 concentration during growth, cold hardening and dehardening: phenology, cold tolerance, photosynthesis and growth.

PubMed

Bigras, F J; Bertrand, A

2006-07-01

Seedlings from a northern and a southern provenance of black spruce (Picea mariana Mill. BSP) from eastern Canada were exposed to 37 or 71 Pa of carbon dioxide (CO2) during growth, cold hardening and dehardening in a greenhouse. Bud phenology, cold tolerance and photosynthetic efficiency were assessed during the growing and over-wintering periods. Bud set occurred earlier in elevated [CO2] than in ambient [CO2], but it was later in the southern provenance than in the northern provenance. An increase in seedling cold tolerance in early fall was related to early bud set in elevated [CO2]. Maximal photosystem II (PSII) photochemical efficiency (F(v)/F(m)), effective quantum yield (phi(PSII)), photochemical quenching (q(P)), light-saturated photosynthesis (Amax), apparent quantum efficiency (alpha'), light-saturated rate of carboxylation (Vcmax) and electron transport (Jmax) decreased during hardening and recovered during dehardening. Although Amax and alpha' were higher in elevated [CO2] when measured at the growth [CO2], down-regulation of photosynthesis occurred in elevated [CO2] as shown by lower F(v)/F(m), phi(PSII), Vcmax and Jmax. Elevated [CO2] reduced gene expression of the small subunit of Rubisco and also decreased chlorophyll a/chlorophyll b ratio and nitrogen concentration in needles, confirming our observation of down-regulation of photosynthesis. Elevated [CO2] increased the CO2 diffusion gradient and decreased photorespiration, which may have contributed to enhance Amax despite down-regulation of photosynthesis. Total seedling dry mass was higher in elevated [CO2] than in ambient [CO2] at the end of the growing season. However, because of earlier bud formation and cold hardening, and down-regulation of photosynthesis during fall and winter in elevated [CO2], the treatment difference in dry mass increment was less by the end of the winter than during the growing season. Differences in photosynthetic rate observed during fall, winter and spring account for the inter-annual variations in carbon assimilation of black spruce seedlings: our results demonstrate that these variations need to be considered in carbon budget studies.

A NEW MODEL TO ESTIMATE DAILY ENERGY EXPENDITURE FOR WINTERING WATERFOWL

EPA Science Inventory

Activity budgets of wintering waterfowl have been widely used to assess habitat quality. However, when factors such as prey abundance or protection from exposure to cold or wind determine quality, measures of daily energy expenditure (DEE) may be more appropriate for this purpos...

Winter photosynthesis in red spruce (Picea rubens Sarg.): limitations, potential benefits, and risks

Treesearch

P.G. Schaberg

2000-01-01

Numerous cold-induced changes in physiology limit the capacity of northern conifers to photosynthesize during winter. Studies of red spruce (Picea rubens Sarg.) have shown that rates of field photosynthesis (Pfield) and laboratory measurements of photosynthetic capacity (Pmax) generally parallel seasonal...

Climatic potential for tourism in the Black Forest, Germany — winter season

NASA Astrophysics Data System (ADS)

Endler, Christina; Matzarakis, Andreas

2011-05-01

Climate change, whether natural or human-caused, will have an impact on human life, including recreation and tourism among other things. In this study, methods from biometeorology and tourism climatology are used to assess the effect of a changed climate on tourism and recreation in particular. The study area is the Black Forest mountainous region of south-west Germany, which is well known for its tourist and recreational assets. Climate model projections for the 2021-2050 period based on REMO-UBA simulations with a high spatial resolution of 10 km are compared to a 30-year reference period (1971-2000) using the IPCC emission scenarios A1B and B1. The results show that the mean winter air temperature will increase by up to 1.8°C, which is the most pronounced warming compared to the other seasons. The annual precipitation amount will increase marginally by 5% in the A1B scenario and 10% in the B1 scenario. Winter precipitation contributes about 10% (A1B) and 30% (B1) to variations in annual precipitation. Although the results show that winter precipitation will increase slightly, snow days affecting skiing will be reduced on average by approximately 40% due to regional warming. Cold stress will be reduced on average by up to 25%. The result is that the thermal environment will be advanced, and warmer winters are likely to lead to an upward altitudinal shift of ski resorts and winter sport activities, thus displacing land-use currently dedicated to nature conservation.

Climatic potential for tourism in the Black Forest, Germany--winter season.

PubMed

Endler, Christina; Matzarakis, Andreas

2011-05-01

Climate change, whether natural or human-caused, will have an impact on human life, including recreation and tourism among other things. In this study, methods from biometeorology and tourism climatology are used to assess the effect of a changed climate on tourism and recreation in particular. The study area is the Black Forest mountainous region of south-west Germany, which is well known for its tourist and recreational assets. Climate model projections for the 2021-2050 period based on REMO-UBA simulations with a high spatial resolution of 10 km are compared to a 30-year reference period (1971-2000) using the IPCC emission scenarios A1B and B1. The results show that the mean winter air temperature will increase by up to 1.8°C, which is the most pronounced warming compared to the other seasons. The annual precipitation amount will increase marginally by 5% in the A1B scenario and 10% in the B1 scenario. Winter precipitation contributes about 10% (A1B) and 30% (B1) to variations in annual precipitation. Although the results show that winter precipitation will increase slightly, snow days affecting skiing will be reduced on average by approximately 40% due to regional warming. Cold stress will be reduced on average by up to 25%. The result is that the thermal environment will be advanced, and warmer winters are likely to lead to an upward altitudinal shift of ski resorts and winter sport activities, thus displacing land-use currently dedicated to nature conservation.

COLD TEMPERATURE MOTOR VEHICLE EMISSIONS TESTING IN ALASKA

EPA Science Inventory

A motor vehicle emissions testing study was conducted in Anchorage and Fairbanks during the winter of 1998-99 to collect actual measurements of initial idle emission rates. The study was performed for a sample of 111 automobiles and light-duty trucks under cold wintertime ambient...

Modeling Shasta Dam operations to regulate temperatures for Chinook salmon under extreme climate and climate change

NASA Astrophysics Data System (ADS)

Dai, A.; Saito, L.; Sapin, J. R.; Rajagopalan, B.; Hanna, R. B.; Kauneckis, D. L.

2014-12-01

Chinook salmon populations have declined significantly after the construction of Shasta Dam on the Sacramento River in 1945 prevented them from spawning in the cold waters upstream. In 1994, the winter-run Chinook were listed under the Endangered Species Act and 3 years later the US Bureau of Reclamation began operating a temperature control device (TCD) on the dam that allows for selective withdrawal for downstream temperature control to promote salmon spawning while also maximizing power generation. However, dam operators are responsible to other interests that depend on the reservoir for water such as agriculture, municipalities, industry, and recreation. An increase in temperatures due to climate change may place additional strain on the ability of dam operations to maintain spawning habitat for salmon downstream of the dam. We examined the capability of Shasta Dam to regulate downstream temperatures under extreme climates and climate change by using stochastically generated streamflow, stream temperature, and weather inputs with a two-dimensional CE-QUAL-W2 model under several operational options. Operation performance was evaluated using degree days and cold pool volume (volume of water below a temperature threshold). Model results indicated that a generalized operations release schedule, in which release elevations varied over the year to match downstream temperature targets, performed best overall in meeting temperature targets while preserving cold pool volume. Releasing all water out the bottom throughout the year tended to meet temperature targets at the expense of depleting the cold pool, and releasing all water out uppermost gates preserved the cold pool, but released water that was too warm during the critical spawning period. With higher air temperatures due to climate change, both degree day and cold pool volume metrics were worse than baseline conditions, which suggests that Chinook salmon may be more negatively affected under climate change.

Response of aboveground carbon balance to long-term, experimental enhancements in precipitation seasonality is contingent on plant community type in cold-desert rangelands

USGS Publications Warehouse

McAbee, Kathryn; Reinhardt, Keith; Germino, Matthew; Bosworth, Andrew

2017-01-01

Semi-arid rangelands are important carbon (C) pools at global scales. However, the degree of net C storage or release in water-limited systems is a function of precipitation amount and timing, as well as plant community composition. In northern latitudes of western North America, C storage in cold-desert ecosystems could increase with boosts in wintertime precipitation, in which climate models predict, due to increases in wintertime soil water storage that enhance summertime productivity. However, there are few long-term, manipulative field-based studies investigating how rangelands will respond to altered precipitation amount or timing. We measured aboveground C pools and fluxes at leaf, soil, and ecosystem scales over a single growing season in plots that had 200 mm of supplemental precipitation added in either winter or summer for the past 21 years, in shrub- and exotic-bunchgrass-dominated garden plots. At our cold-desert site (298 mm precipitation during the study year), we hypothesized that increased winter precipitation would stimulate the aboveground C uptake and storage relative to ambient conditions, especially in plots containing shrubs. Our hypotheses were generally supported: ecosystem C uptake and long-term biomass accumulation were greater in winter- and summer-irrigated plots compared to control plots in both vegetation communities. However, substantial increases in the aboveground biomass occurred only in winter-irrigated plots that contained shrubs. Our findings suggest that increases in winter precipitation will enhance C storage of this widespread ecosystem, and moreso in shrub- compared to grass-dominated communities.

Response of aboveground carbon balance to long-term, experimental enhancements in precipitation seasonality is contingent on plant community type in cold-desert rangelands.

PubMed

McAbee, Kathryn; Reinhardt, Keith; Germino, Matthew J; Bosworth, Andrew

2017-03-01

Semi-arid rangelands are important carbon (C) pools at global scales. However, the degree of net C storage or release in water-limited systems is a function of precipitation amount and timing, as well as plant community composition. In northern latitudes of western North America, C storage in cold-desert ecosystems could increase with boosts in wintertime precipitation, in which climate models predict, due to increases in wintertime soil water storage that enhance summertime productivity. However, there are few long-term, manipulative field-based studies investigating how rangelands will respond to altered precipitation amount or timing. We measured aboveground C pools and fluxes at leaf, soil, and ecosystem scales over a single growing season in plots that had 200 mm of supplemental precipitation added in either winter or summer for the past 21 years, in shrub- and exotic-bunchgrass-dominated garden plots. At our cold-desert site (298 mm precipitation during the study year), we hypothesized that increased winter precipitation would stimulate the aboveground C uptake and storage relative to ambient conditions, especially in plots containing shrubs. Our hypotheses were generally supported: ecosystem C uptake and long-term biomass accumulation were greater in winter- and summer-irrigated plots compared to control plots in both vegetation communities. However, substantial increases in the aboveground biomass occurred only in winter-irrigated plots that contained shrubs. Our findings suggest that increases in winter precipitation will enhance C storage of this widespread ecosystem, and moreso in shrub- compared to grass-dominated communities.

Late winter under ice pelagic microbial communities in the high Arctic Ocean and the impact of short-term exposure to elevated CO2 levels

PubMed Central

Monier, Adam; Findlay, Helen S.; Charvet, Sophie; Lovejoy, Connie

2014-01-01

Polar Oceans are natural CO2 sinks because of the enhanced solubility of CO2 in cold water. The Arctic Ocean is at additional risk of accelerated ocean acidification (OA) because of freshwater inputs from sea ice and rivers, which influence the carbonate system. Winter conditions in the Arctic are of interest because of both cold temperatures and limited CO2 venting to the atmosphere when sea ice is present. Earlier OA experiments on Arctic microbial communities conducted in the absence of ice cover, hinted at shifts in taxa dominance and diversity under lowered pH. The Catlin Arctic Survey provided an opportunity to conduct in situ, under-ice, OA experiments during late Arctic winter. Seawater was collected from under the sea ice off Ellef Ringnes Island, and communities were exposed to three CO2 levels for 6 days. Phylogenetic diversity was greater in the attached fraction compared to the free-living fraction in situ, in the controls and in the treatments. The dominant taxa in all cases were Gammaproteobacteria but acidification had little effect compared to the effects of containment. Phylogenetic net relatedness indices suggested that acidification may have decreased the diversity within some bacterial orders, but overall there was no clear trend. Within the experimental communities, alkalinity best explained the variance among samples and replicates, suggesting subtle changes in the carbonate system need to be considered in such experiments. We conclude that under ice communities have the capacity to respond either by selection or phenotypic plasticity to heightened CO2 levels over the short term. PMID:25324832

Seasonality recorded in Modern and Viking Limpet Shells ( Patella vulgata), Quoygrew, Orkney, UK

NASA Astrophysics Data System (ADS)

Surge, D.; Barrett, J. H.; Milner, N.

2007-12-01

Climate archives contained in shells of the European limpet, Patella vulgata, from Viking shell middens can potentially provide much needed information about seasonality in mid-latitude coastal areas prior to the complicating effects of industrialization. P. vulgata shells are common in the stratified middens accumulated by the Viking inhabitants of Quoygrew, Orkney, and were likely used for baiting fish. Radiocarbon dates and artifacts place these middens between the 9th/10th and 13th centuries. This interval coincides with the Medieval Warm Period. Little is known about the seasonal temperature variation during this time of pre-industrial warming. Before reconstructing climate information from Viking shells, we determined whether P. vulgata preserves environmental and ecological information. Previous work on live-collected specimens from Whitley Bay near Newcastle-upon-Tyne, England, confirmed that: (1) oxygen isotope ratios served as a proxy for sea surface temperature after accounting for a uniform +1.01 +/-0.21 ‰ offset; and (2) annual growth lines occurred during the winter given this location is within the cold-temperature biogeographic province. Winter growth lines and increments are common growth patterns found in marine bivalves from the cold-temperate province along the western North Atlantic. Preliminary isotope data from the 9th/10th century reveals similar winter and summer temperature relative to today and annual growth lines formed during winter, typical of a cold-temperate habitat.

Dehydration in the Winter Arctic Tropopause Region

NASA Technical Reports Server (NTRS)

Pfister, Leonhard; Jensen, Eric; Podolske, James; Selkirk, Henry; Anderson, Bruce; Avery, Melody; Diskin. Glenn

2004-01-01

Recent work has shown that limited amounts of tropospheric air can penetrate as much as 1 km into the middleworld stratosphere during the arctic winter. This, coupled with temperatures that are cold enough to produce saturation mixing ratios of less than 5 ppmv at the tropopause, results in stratospheric cloud formation and upper tropospheric dehydration. Even though these "cold outbreaks" occupy only a small portion of the area in the arctic (1-2%), their importance is magnified by an order of magnitude because of the air flow through them. This is reinforced by evidence of progressive drying through the winter measured during SOLVE-1. The significance of this process lies in its effect on the upper tropospheric water content of the middle and high latitude tropopause region, which plays an important role in regulating the earth's radiative balance. There appears to be significant year-to-year variability in the incidence of the cold outbreaks. This work has two parts. First, we describe case studies of dehydration taken from the SOLVE and SOLVE2 aircraft sampling missions during the Arctic winters of 2000 and 2003 respectively. Trajectory based microphysical modeling is employed to examine the sensitivity of the dehydration to microphysical parameters and the nature of sub-grid scale temperature fluctuations. We then examine the year-to-year variations in potential dehydration using a trajectory climatology.

Partitioning of water flux in a Sierra Nevada ponderosa pine plantation

USGS Publications Warehouse

Kurpius, M.R.; Panek, J.A.; Nikolov, N.T.; McKay, M.; Goldstein, Allen H.

2003-01-01

The weather patterns of the west side of the Sierra Nevada Mountains (cold, wet winters and hot, dry summers) strongly influence how water is partitioned between transpiration and evaporation and result in a specific strategy of water use by ponderosa pine trees (Pinus ponderosa) in this region. To investigate how year-round water fluxes were partitioned in a young ponderosa pine ecosystem in the Sierra Nevada Mountains, water fluxes were continually measured from June 2000 to May 2001 using a combination of sap flow and eddy covariance techniques (above- and below-canopy). Water fluxes were modeled at our study site using a biophysical model, FORFLUX. During summer and fall water fluxes were equally partitioned between transpiration and soil evaporation while transpiration dominated the water fluxes in winter and spring. The trees had high rates of canopy conductance and transpiration in the early morning and mid-late afternoon and a mid-day depression during the dry season. We used a diurnal centroid analysis to show that the timing of high canopy conductance and transpiration relative to high vapor pressure deficit (D) shifted with soil moisture: during periods of low soil moisture canopy conductance and transpiration peaked early in the day when D was low. Conversely, during periods of high soil moisture canopy conductance and transpiration peaked at the same time or later in the day than D. Our observations suggest a general strategy by the pine trees in which they maximize stomatal conductance, and therefore carbon fixation, throughout the day on warm sunny days with high soil moisture (i.e. warm periods in winter and late spring) and maximize stomatal conductance and carbon fixation in the morning through the dry periods. FORFLUX model estimates of evaporation and transpiration were close to measured/calculated values during the dry period, including the drought, but underestimated transpiration and overestimated evaporation during the wet period. ?? 2003 Elsevier Science B.V. All rights reserved.

The sweet cherry (Prunus avium) FLOWERING LOCUS T gene is expressed during floral bud determination and can promote flowering in a winter-annual Arabidopsis accession.

PubMed

Yarur, Antonia; Soto, Esteban; León, Gabriel; Almeida, Andrea Miyasaka

2016-12-01

FT gene is expressed in leaves and buds and is involved in floral meristem determination and bud development in sweet cherry. In woody fruit perennial trees, floral determination, dormancy and bloom, depends on perception of different environmental and endogenous cues which converge to a systemic signaling gene known as FLOWERING LOCUS T (FT). In long-day flowering plants, FT is expressed in the leaves on long days. The protein travels through the phloem to the shoot apical meristem, where it induces flower determination. In perennial plants, meristem determination and flowering are separated by a dormancy period. Meristem determination takes place in summer, but flowering occurs only after a dormancy period and cold accumulation during winter. The roles of FT are not completely clear in meristem determination, dormancy release, and flowering in perennial plants. We cloned FT from sweet cherry (Prunus avium) and analyzed its expression pattern in leaves and floral buds during spring and summer. Phylogenetic analysis shows high identity of the FT cloned sequence with orthologous genes from other Rosaceae species. Our results show that FT is expressed in both leaves and floral buds and increases when the daylight reached 12 h. The peak in FT expression was coincident with floral meristem identity genes expression and morphological changes typical of floral meristem determination. The Edi-0 Arabidopsis ecotype, which requires vernalization to flower, was transformed with a construct for overexpression of PavFT. These transgenic plants showed an early-flowering phenotype without cold treatment. Our results suggest that FT is involved in floral meristem determination and bud development in sweet cherry. Moreover, we show that FT is expressed in both leaves and floral buds in this species, in contrast to annual plants.

Vanishing river ice cover in the lower part of the Danube basin - signs of a changing climate.

PubMed

Ionita, M; Badaluta, C -A; Scholz, P; Chelcea, S

2018-05-21

Many of the world's largest rivers in the extra tropics are covered with ice during the cold season, and in the Northern Hemisphere approximately 60% of the rivers experience significant seasonal effects of river ice. Here we present an observational data set of the ice cover regime for the lower part of the Danube River which spans over the period 1837-2016, and its the longest one on record over this area. The results in this study emphasize the strong impact of climate change on the occurrence of ice regime especially in the second part of the 20 th century. The number of ice cover days has decreased considerably (~28days/century) mainly due to an increase in the winter mean temperature. In a long-term context, based on documentary evidences, we show that the ice cover occurrence rate was relatively small throughout the Medieval Warm Period (MWP), while the highest occurrence rates were found during the Maunder Minimum and Dalton Minimum periods. We conclude that the river ice regime can be used as a proxy for the winter temperature over the analyzed region and as an indicator of climate-change related impacts.

Record-breaking Ozone Loss during Arctic Winter 2010/2011: Comparison with Arctic Winter 1996/1997

NASA Astrophysics Data System (ADS)

Godin Beekmann, S.; Kuttipurath, J.; Lefèvre, F.; Santee, M. L.; Froidevaux, L.

2011-12-01

Polar processing and chemical ozone loss is analysed during the Arctic winter/spring 2010/2011. The analyses with temperatures and potential vorticity (PV) data show a prolonged vortex from early December through mid-April. The PV maps illustrate strong vortex persistence in the lower stratosphere between 450 and 675 K, showing similar evolution with time. The minimum temperatures extracted from ECMWF data at 40-90°N show values below 195 K for a record period of first week of December through second week of April, indicating the longest period of colder temperatures for 17 years. At 10 hPa, there was a warming of about 10 K at 60°N and 40 K at 90°N around mid-January. The heat flux also showed high values in line with the increase in temperatures, of about 425 m K/s at 60°N at the same pressure level. However, the westerlies were strong (e.g. 35-45 m/s at 60°N) enough to keep the vortex intact until mid-April. Because of the cold temperatures in late winter and early spring, large areas of Polar Stratospheric Clouds (PSC) were found in the 400-600 K isentropic level range. Though the maximum values of PSCs area are smaller compared to other cold winters such as 2005, the extended period of presence of PSCs during this winter was exceptional, especially in late February-mid-March, in agreement with the cold temperatures during the period. Ozone loss analyses with high resolution Mimosa-Chim chemical transport model simulations show that the loss started by early January, and was about 0.5 ppmv in late January. The loss progressed slowly to 1 ppmv by the end of February, and then intensified by early March. The ozone depletion estimated by the passive method finds a maximum value of about 2-2.3 ppmv by the end of March-early April in the 450-550K range inside the vortex, which coincides with the areas of PSCs and high chlorine activation. This is the largest loss ever estimated with this model for any Arctic winter. It is consistent with the unprecedented chlorine activation that occurred in the winter, as the modeled ClO values show about 1.7 ppbv in early January and about 1 ppbv in March at 450-550K. This is longest period of chlorine activation noted among the Arctic winters. The ozone partial column loss reaches about 115-150 DU in the range 350 - 550 K. These model results for ozone, ozone loss and ClO are in good agreement with those found from Aura Microwave Limb Sounder observations. Since the winter 1996/1997 was also very cold in March - April, a comparison between both winters 2011 and 1997 will be presented, based on temperature, PV, Heat flux data and ozone loss estimations. Similarities and differences in the polar processing and ozone loss during both winters will be discussed using various measurements and model simulations. Copyright 2011. All rights reserved.

Stephen Jay Gould and the Value of Neutrality of Science During the Cold War.

PubMed

Sheldon, Myrna

2016-12-01

Stephen Jay Gould was a paleontologist and scientific celebrity at the close of the twentieth century, most famous for his popular writings on evolution and his role in the American creationist controversies of that era. In the early 1980s, Gould was drawn into the "nuclear winter" episode through his friendship with Carl Sagan, an astronomer and popular science celebrity. Sagan helped develop the theory of nuclear winter and subsequently used the theory as evidence to petition the United States government to scale back its nuclear armament. The theory of nuclear winter claimed that even a small nuclear exchange could result in a atmospheric blackening akin to the extinction event of the late Cretaceous. Gould was not a climate scientist but he testified before the U.S. House of Representatives as an expert on historical extinction events. Gould's insistence on the value-neutrality of nuclear winter reveals much about the moral politics of science in late Cold War America. Coming at the heels of leftist scientific activism of the 1980s, the nuclear winter episode demonstrates how value-neutrality emerged the salient feature of scientific involvement in American politics in this period. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bridging among disciplines by synthesizing soil and plant processes (advances in agricultural systems)

USDA-ARS?s Scientific Manuscript database

Location specific consequences of GCM projected climate change on over-wintering crops like winter wheat can vary geographically (latitude and longitude) depending on the severity and duration of the cold period and other factors like the altitude, precipitation distribution, and photoperiod. The US...

Grapevine winter survival and prospects in an age of changing climate

USDA-ARS?s Scientific Manuscript database

Vines transition from active growth to dormancy by processes controlled by genes, but are greatly influenced by variation in weather conditions - even in the coldest part of the winter. My research program, known as the USDA Cold Hardiness Genetics Research Program, seeks to understand how a vine's...

Diapause and overwintering of two spruce bark beetle species

Treesearch

Martin Schebeck; E. Matthew Hansen; Axel Schopf; Gregory J. Ragland; Christian Stauffer; Barbara J. Bentz

2017-01-01

Diapause, a strategy to endure unfavourable conditions (e.g. cold winters) is commonly found in ectothermic organisms and is characterized by an arrest of development and reproduction, a reduction ofmetabolic rate, and an increased resistance to adversity. Diapause, in addition to adaptations for surviving low winter temperatures, significantly influences phenology,...

Deadly Cold: Health Hazards Due to Cold Weather. An Information Paper by the Subcommittee on Health and Long-Term Care of the Select Committee on Aging. House of Representatives, Ninety-Eighth Congress, Second Session (February 1984).

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. House Select Committee on Aging.

This paper, on the health hazards of cold weather for elderly persons, presents information from various sources on the death rates in winter throughout the United States. After reviewing the scope of the problem, specific health hazards associated with cold weather are discussed, i.e., hypothermia, fires, carbon monoxide poisoning, and influenza…

The Arctic Vortex in March 2011: A Dynamical Perspective

NASA Technical Reports Server (NTRS)

Hurwitz, Margaret M.; Newman, Paul A.; Garfinkel,Chaim I.

2011-01-01

Despite the record ozone loss observed in March 2011, dynamical conditions in the Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving in February preceded cold anomalies in t he polar lower stratosphere in March and a relatively late breakup of the Arctic vortex in April. La Nina conditions and the westerly phas e of the quasi-biennial oscillation (QBO) were observed in March 201 1. Though these conditions are generally associated with a stronger vortex in mid-winter, the respective cold anomalies do not persist t hrough March. Therefore, the La Nina and QBO-westerly conditions cannot explain the observed cold anomalies in March 2011. In contrast, po sitive sea surface temperature anomalies in the North Pacific may ha ve contributed to the unusually weak tropospheric wave driving and s trong Arctic vortex in late winter 2011.

Comparative analysis of the cold acclimation and freezing tolerance capacities of seven diploid Brachypodium distachyon accessions

PubMed Central

Colton-Gagnon, Katia; Ali-Benali, Mohamed Ali; Mayer, Boris F.; Dionne, Rachel; Bertrand, Annick; Do Carmo, Sonia; Charron, Jean-Benoit

2014-01-01

Background and Aims Cold is a major constraint for cereal cultivation under temperate climates. Winter-hardy plants interpret seasonal changes and can acquire the ability to resist sub-zero temperatures. This cold acclimation process is associated with physiological, biochemical and molecular alterations in cereals. Brachypodium distachyon is considered a powerful model system to study the response of temperate cereals to adverse environmental conditions. To date, little is known about the cold acclimation and freezing tolerance capacities of Brachypodium. The main objective of this study was to evaluate the cold hardiness of seven diploid Brachypodium accessions. Methods An integrated approach, involving monitoring of phenological indicators along with expression profiling of the major vernalization regulator VRN1 orthologue, was followed. In parallel, soluble sugars and proline contents were determined along with expression profiles of two COR genes in plants exposed to low temperatures. Finally, whole-plant freezing tests were performed to evaluate the freezing tolerance capacity of Brachypodium. Key Results Cold treatment accelerated the transition from the vegetative to the reproductive phase in all diploid Brachypodium accessions tested. In addition, low temperature exposure triggered the gradual accumulation of BradiVRN1 transcripts in all accessions tested. These accessions exhibited a clear cold acclimation response by progressively accumulating proline, sugars and COR gene transcripts. However, whole-plant freezing tests revealed that these seven diploid accessions only have a limited capacity to develop freezing tolerance when compared with winter varieties of temperate cereals such as wheat and barley. Furthermore, little difference in terms of survival was observed among the accessions tested despite their previous classification as either spring or winter genotypes. Conclusions This study is the first to characterize the freezing tolerance capacities of B. distachyon and provides strong evidence that some diploid accessions such as Bd21 have a facultative growth habit. PMID:24323247

Dehydration and Lagrangian Cold Point in the extratropical Tropopause region

NASA Astrophysics Data System (ADS)

Hoor, P.; Wernli, H.

2012-04-01

The tropopause region of the tropics and extratropics is sensitive to modifications of the radiation budget through changes of radiatively active substances like ozone and water vapour. Both may also modify the temperature structure and the strengths of the tropopause inversion layer (TIL). Stratospheric water vapour is mainly controlled by dehydration in the tropics. Ascending air masses encounter their minimum temperature in the TTL region (tropical tropopause layer) which determines the water vapour fraction which enters the stratosphere. In the lowermost stratosphere of the extratropics however, the tropical signal might be lost due to mixing with airmasses which crossed the tropopause (TST: troposphere to stratosphere) at higher temperatures, therefore carrying more water vapour to the extratropical stratosphere. We investigate statistical 90 day backward trajectories to investigate the role of dehydration at the extratropical tropopause for the water vapour budget at the tropopause at mid and high latitudes. We use a set of 800000 trajectories for summer and winter, respectively, on the basis of ECMWF-T799L91 operational data (kinematic wind fields). We analyze the trajectories for the time and locations of their cold point and TST. Our results indicate that : 1) TST and dehydration occur at different locations 2) Dehydration occurs in general before trajectories enter the stratosphere 3) Dehydration of TST trajectories can occur in northern winter after TST in the region of high tropopauses over Siberia

Interannual changes in snow cover and its impact on ground surface temperatures in Livingston Island (Antarctica)

NASA Astrophysics Data System (ADS)

Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

2015-04-01

In permafrost areas the seasonal snow cover is an important factor on the ground thermal regime. Snow depth and timing are important in ground insulation from the atmosphere, creating different snow patterns and resulting in spatially variable ground temperatures. The aim of this work is to characterize the interactions between ground thermal regimes and snow cover and the influence on permafrost spatial distribution. The study area is the ice-free terrains of northwestern Hurd Peninsula in the vicinity of the Spanish Antarctic Station "Juan Carlos I" and Bulgarian Antarctic Station "St. Kliment Ohridski". Air and ground temperatures and snow thickness data where analysed from 4 sites along an altitudinal transect in Hurd Peninsula from 2007 to 2012: Nuevo Incinerador (25 m asl), Collado Ramos (110 m), Ohridski (140 m) and Reina Sofia Peak (275 m). The data covers 6 cold seasons showing different conditions: i) very cold with thin snow cover; ii) cold with a gradual increase of snow cover; iii) warm with thick snow cover. The data shows three types of periods regarding the ground surface thermal regime and the thickness of snow cover: a) thin snow cover and short-term fluctuation of ground temperatures; b) thick snow cover and stable ground temperatures; c) very thick snow cover and ground temperatures nearly constant at 0°C. a) Thin snow cover periods: Collado Ramos and Ohridski sites show frequent temperature variations, alternating between short-term fluctuations and stable ground temperatures. Nuevo Incinerador displays during most of the winter stable ground temperatures; b) Cold winters with a gradual increase of the snow cover: Nuevo Incinerador, Collado Ramos and Ohridski sites show similar behavior, with a long period of stable ground temperatures; c) Thick snow cover periods: Collado Ramos and Ohridski show long periods of stable ground, while Nuevo Incinerador shows temperatures close to 0°C since the beginning of the winter, due to early snow cover, which prevents cooling. Reina Sofia shows a very different behavior from the other sites, with a frequent stabilization of ground temperatures during all the winters, and last until late-fall. This situation could be related to the structure, and physical and thermal properties of snow cover. The analysis of the Freezing Degree Days (FDDs) and freezing n-factor reveals significant interannual variations. Ohridski shows the highest FDDs values followed by Reina Sofia. Nuevo Incinerador showed the lowest FDDs values. The freezing n-factor shows highest values at Ohridski, followed by Collado Ramos and Reina Sofia with very similar values. Nuevo Incinerador shows the lowest n-factor values. Snow cover doesn't insulate the ground from freezing, but depending on its thickness, density and the amount of heat in the ground, it decreases ground temperatures amplitudes and increases delays relative to air temperature changes. Even where snow cover remains several centimeters thick for several months, slow decrease of bottom temperature is possible, reaching a minimum value at the end of the winter. The results demonstrate that Reina Sofia and Ohridski sites, because of the seasonal behavior, FDDs and freezing n-factor, demonstrate higher winter ground cooling. This research was funded by PERMANTAR-3 (PTDC/AAG-GLO/3908/2012) project (Fundação para a Ciência e a Tecnologia of Portugal)

Body temperature responses to handling stress in wintering Black-capped Chickadees (Poecile atricapillus L.).

PubMed

Lewden, Agnès; Nord, Andreas; Petit, Magali; Vézina, François

2017-10-01

Body temperature variation in response to acute stress is typically characterized by peripheral vasoconstriction and a concomitant increase in core body temperature (stress-induced hyperthermia). It is poorly understood how this response differs between species and within individuals of the same species, and how it is affected by the environment. We therefore investigated stress-induced body temperature changes in a non-model species, the Black-capped Chickadee, in two environmental conditions: outdoors in low ambient temperature (mean: -6.6°C), and indoors, in milder ambient temperature close to thermoneutrality (mean: 18.7°C). Our results show that the change in body temperature in response to the same handling stressor differs in these conditions. In cold environments, we noted a significant decrease in core body temperature (-2.9°C), whereas the response in mild indoor conditions was weak and non-significant (-0.6°C). Heat loss in outdoor birds was exacerbated when birds were handled for longer time. This may highlight the role of behavioral thermoregulation and heat substitution from activity to body temperature maintenance in harsh condition. Importantly, our work also indicates that changes in the physical properties of the bird during handling (conductive cooling from cold hands, decreased insulation from compression of plumage and prevention of ptiloerection) may have large consequences for thermoregulation. This might explain why females, the smaller sex, lost more heat than males in the experiment. Because physiological and physical changes during handling may carry over to affect predation risk and maintenance of energy balance during short winter days, we advice caution when designing experimental protocols entailing prolonged handling of small birds in cold conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

An Overview of the Uintah Basin Winter Ozone Study Intensives: 2012, 2013, and 2014

NASA Astrophysics Data System (ADS)

Roberts, J. M.; Edwards, P. M.; Brown, S. S.; Ahmadov, R.; Bates, T. S.; De Gouw, J. A.; Gilman, J.; Graus, M.; Helmig, D.; Koss, A.; Langford, A. O.; Lefer, B. L.; Lerner, B. M.; Li, R.; Li, S. M.; Liggio, J.; McKeen, S. A.; McLaren, R.; Parrish, D. D.; Quinn, P.; Senff, C. J.; Stutz, J.; Thompson, C. R.; Tsai, J. Y.; Veres, P. R.; Washenfelder, R. A.; Warneke, C.; Wild, R. J.; Young, C.; Yuan, B.

2014-12-01

Ground level ozone frequently exceeds the National Ambient Air Quality Standard in the Uintah Basin in northeastern Utah during the winter season. The basin is home to some of the most intensive oil and gas production in the region, activities that have been accelerated by new technologies in that industry. High ozone episodes are coincident with the presence of snow and "cold pool" conditions during which a stable shallow boundary layer persists for periods of up to 10 days. Local emissions of NOx and VOCs build up within this layer, but the sources of radicals that initiate the photochemistry have been unclear since low photolysis rates and water vapor make the traditional channel, ozone photolysis, quite inefficient. Intensive studies over the past 3 winter seasons have shown that unconventional radical sources; primarily carbonyls, and to a lesser extent nitryl chloride and nitrous acid, are responsible for radical production in this environment. The role of snow cover is to restrict vertical mixing, enhance photolysis rates through increased albedo, and reduce ozone deposition. The uptake and production of photo-labile species on the snow surface were observed, but appear to have only minor influences on the ozone photochemistry.

Energy Homeostasis in Monotremes

PubMed Central

Nicol, Stewart C.

2017-01-01

In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles and mammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between “higher mammals” and “lower vertebrates.” Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions. Because the short-beaked echidna Tachyglossus aculeatus, may show very large daily variations in body temperature, as well as seasonal hibernation, it has been suggested that it may provide a useful model of protoendotherm physiology. Such analysis is complicated by the very significant differences in thermal relations between echidnas from different climates. In all areas female echidnas regulate Tb within 1°C during egg incubation. The lactation period is considered to be the most energetically expensive time for most female mammals but lactating echidnas showed no measurable difference in field metabolic rate from non-lactating females, while the lactation period is more than 200 days for Kangaroo Island echidnas but only 150 days in Tasmania. In areas with mild winters echidnas show reduced activity and shallow torpor in autumn and early winter, but in areas with cold winters echidnas enter true hibernation with Tb falling as low as 4.5°C. Monotremes do not possess brown adipose tissue and maximum rates of rewarming from hibernation in echidnas were only half those of marmots of the same mass. Although echidnas show very large seasonal variations in fat stores associated with hibernation there is no relationship between plasma leptin and adiposity. Leptin levels are lowest during post-reproductive fattening, supporting suggestions that in evolutionary terms the anorectic effects of leptin preceded the adiposity signal. BMR of platypuses is twice that of echidnas although maximum metabolism is similar. High levels of thyroid hormones in platypuses may be driving metabolism limited by low body temperature. Monotremes show a mosaic of plesiomorphic and derived features but can still inform our understanding of the evolution of endothermy. PMID:28484364

Characterising freeze in the UK: applications for the insurance industry

NASA Astrophysics Data System (ADS)

Raven, E. K.; Keef, C.; Busby, K.

2012-04-01

The UK winters of 2009-2010 and 2010-2011 were characterised by prolonged and widespread low temperatures. This was challenging for the UK insurance industry and organisations such as the emergency services, the Highways Agency and British Gas who had to manage the extra demands that resulted. In the 6-day period running to Christmas Eve 2010, British Gas reported 100,000 boiler repair call-outs, whilst those 190,000 homes and businesses left with frozen and subsequently burst pipes contributed to the ABI's estimated £ 900 million in insured losses for December 2010 alone; the highest payout by the industry for damages associated with cold weather. Unfortunately, the severity of these winters made the difference between profit and loss for some primary UK insurance companies. To enable better pricing of premiums in the future, insurance companies are looking to understand the potential risk from cold waves at a local, postcode-level, whilst reinsurance firms seek to determine the accumulated loss across the UK associated with spatially coherent events. Other industry sectors also strive to improve their understanding of weather extremes for planning and management. Underpinning this is the need to statistically characterise the physical hazard. Aimed primarily at the re/insurance industry, we have applied an established methodology for developing statistical event sets and applied this to generate a UK freeze event set. An event set provides a stochastic set of several thousand events over 10's of 1000's of years and is typically applied within probabilistic catastrophe models. Our method applies extreme value theory and dependence modelling to explain low-temperature relationships across the UK and over time using historical records. The resulting event set represents the spatial and temporal dependence of cold waves in the UK and is modelled against household factors that increase the vulnerability to freezing conditions, such as property type, age and condition. By presenting our methodology, we illustrate some of the complex spatial and temporal relationships in UK freeze events and place the past two winters into a statistical context. Furthermore, we demonstrate the application of event sets within catastrophe modelling and risk mapping services.

Cold Tolerance of Pityophthorus juglandis (Coleoptera: Scolytidae) From Northern California

Treesearch

Andrea R. Hefty; Steven J. Seybold; Brian H. Aukema; Robert C. Venette

2017-01-01

Winter survivorship of insects is determined by a combination of physiological, behavioral, and microhabitat characteristics. We characterized the cold tolerance of the walnut twig beetle, Pityophthorus juglandis Blackman, a domestic alien invasive bark beetle that vectors a phytopathogenic fungus. The beetle and fungus cause thousand cankers...

Temperature dependent RNA metabolism in Xylella fastidiosa during cold stress and grapevine infection

USDA-ARS?s Scientific Manuscript database

Re-occurrence of Pierce’s disease of grapes, caused by Xylella fastidiosa, is known to be influenced by environmental factors, particularly cold temperatures during overwintering. Grapevines in colder regions are often cured of X. fastidiosa infection over the winter season, depending on cultivar, t...

In Vitro Evaluation Mimics Influences of Winter Cold Water Ingestion on Ruminal Function

USDA-ARS?s Scientific Manuscript database

Ingestion of cold feed and water may suddenly reduce ruminal temperature, which could result in decreased microbial activity and diet digestibility. The objective of this study was to investigate the association between critical rumen in vitro incubation temperature and activity of ruminal microorga...

In vitro evaluation mimics influences of winter cold water ingestion on ruminal function

USDA-ARS?s Scientific Manuscript database

Ingestion of cold feed and water may suddenly reduce ruminal temperature, which could result in decreased microbial activity and diet digestibility. The objective of this study was to investigate the association between critical rumen in vitro incubation temperature and activity of ruminal microorga...

Determining the spatial variability of crop yields of two different climatic regions in Southwest Germany

NASA Astrophysics Data System (ADS)

Eshonkulov, Ravshan; Poyda, Arne; Ingwersen, Joachim; Streck, Thilo

2017-04-01

Assessing the spatial variability of soil physical properties is crucial for agricultural land management. We determined the spatial variability within two agricultural fields in the regions of Kraichgau and Swabian Jura in Southwest Germany. We determined soil physical properties and recorded the temporal development of soil mineral nitrogen (N) and water content as well as that of plant variables (phenology, biomass, leaf area index (LAI), N content, green vegetation fraction (GVF). The work was conducted during the vegetation periods of 2015 and 2016 in winter wheat, and winter rapeseed in Kraichgau and winter barley and silage maize on Swabian Jura. Measurements were taken in three-weekly intervals. On each field, we identified three plots with reduced plant development using high-resolution (RapidEye) satellite images ("cold spots"). Measurements taken on these cold spots were compared to those from five established (long-term) reference plots representing the average field variability. The software EXPERT-N was used to simulate the soil crop system at both cold spots and reference plots. Sensitivity analyses were conducted to identify the most important parameters for the determination of spatial variability in crop growth dynamics.

Climate Degradation and Extreme Icing Events Constrain Life in Cold-Adapted Mammals.

PubMed

Berger, J; Hartway, C; Gruzdev, A; Johnson, M

2018-01-18

Despite the growth in knowledge about the effects of a warming Arctic on its cold-adapted species, the mechanisms by which these changes affect animal populations remain poorly understood. Increasing temperatures, declining sea ice and altered wind and precipitation patterns all may affect the fitness and abundance of species through multiple direct and indirect pathways. Here we demonstrate previously unknown effects of rain-on-snow (ROS) events, winter precipitation, and ice tidal surges on the Arctic's largest land mammal. Using novel field data across seven years and three Alaskan and Russian sites, we show arrested skeletal growth in juvenile muskoxen resulting from unusually dry winter conditions and gestational ROS events, with the inhibitory effects on growth from ROS events lasting up to three years post-partum. Further, we describe the simultaneous entombment of 52 muskoxen in ice during a Chukchi Sea winter tsunami (ivuniq in Iñupiat), and link rapid freezing to entrapment of Arctic whales and otters. Our results illustrate how once unusual, but increasingly frequent Arctic weather events affect some cold-adapted mammals, and suggest that an understanding of species responses to a changing Arctic can be enhanced by coalescing groundwork, rare events, and insights from local people.

Variability in the combustion-derived fraction of urban humidity in Salt Lake City winter estimated from stable water vapor isotopes and its relationship to atmospheric stability and inversion structure

NASA Astrophysics Data System (ADS)

Fiorella, R.; Bares, R.; Lin, J. C.; Strong, C.; Bowen, G. J.

2017-12-01

Water released from the combustion of fossil fuels, while a negligible part of the global hydrological cycle, may be a significant contributor to urban humidity as fossil fuel emissions are strongly concentrated in space and time. The fraction of urban humidity comprised of combustion-derived vapor (CDV) cannot be observed through humidity measurements alone. However, the distinct stable isotopic composition of CDV, which arises from the reaction of 18O-enriched atmospheric O2 with 2H-depleted organic molecules, represents a promising method to apportion observed humidity between CDV and advected vapor. We apply stable water vapor isotopes to investigate variability in CDV amount and its relationship to atmospheric conditions in Salt Lake City, Utah. The Salt Lake Valley experiences several periods of atmospheric stratification during winter known as cold air pools, during which concentrations of CDV and pollutants can be markedly elevated due to reduced atmospheric mixing. Therefore, the SLV during winter is an ideal place to investigate variability in CDV fraction across a spectrum of boundary layer conditions, ranging from well-mixed to very stable. We present water vapor isotope data from four winters (2013-2017) from the top of a 30 m building on the University of Utah (U of U) Campus. Additionally, we present water vapor isotope data from the summit of Hidden Peak from the 2016-2017 winter, 25 km SE and 2000 m above the U of U site. The Hidden Peak site is consistently above the cold air pool emplaced in the SLV during stable events. We find the expression of the CDV signal in the valley is related to the atmospheric structure of the cold air pools in the SLV, and that the fraction of CDV inferred in the valley is likely related to the mixing height within the cold air pool. Furthermore, we find that patterns between the Hidden Peak and U of U sites during inversion events may record the large-scale atmospheric dynamics promoting emplacement of the cold air pool in the SLV. Further refinements of CDV estimation through stable isotope methods will bring improved mechanistic understanding of the role of CDV in the urban hydrological cycle and improve model simulations of urban environments.

Physiological disturbances and overwinter mortality of largemouth bass from different latitudes.

PubMed

VanLandeghem, Matthew M; Wagner, Curtis P; Wahl, David H; Suski, Cory D

2013-01-01

Thermal conditions associated with winter can influence the distribution of a species. Because winter severity varies along latitudes, populations of temperate fish located along a latitudinal gradient may display variation in both sublethal and lethal responses to cold stressors. Sublethal physiological disturbances were quantified in age 1 largemouth bass (Micropterus salmoides) from populations originating from Alabama and Illinois but raised in a common environment. Fish were exposed to 6 h of rapid cold shock from 20° to 8°C (controls were held at 20°C) and then sampled for white muscle, whole blood, and plasma. After cold shock, glucose concentrations were elevated in Alabama but not Illinois fish. Sodium was lower and chloride was higher in Alabama largemouth bass, but fish from Illinois had a greater propensity for potassium loss during cold shock. In Illinois ponds, Alabama largemouth bass exhibited lower overwinter survival (adult: 10%; age 0: 22%) than did those from Illinois (adult: 80%; age 0: 82%). Latitudinal variation in physiological responses to cold stressors may therefore influence overwinter survival of largemouth bass and the ability of a fish species to exist over large geographic areas.

Temperature characteristics of winter roost-sites for birds and mammals: tree cavities and anthropogenic alternatives

NASA Astrophysics Data System (ADS)

Grüebler, Martin U.; Widmer, Silv; Korner-Nievergelt, Fränzi; Naef-Daenzer, Beat

2014-07-01

The microclimate of potential roost-sites is likely to be a crucial determinant in the optimal roost-site selection of endotherms, in particular during the winter season of temperate zones. Available roost-sites for birds and mammals in European high trunk orchards are mainly tree cavities, wood stacks and artificial nest boxes. However, little is known about the microclimatic patterns inside cavities and thermal advantages of using these winter roost-sites. Here, we simultaneously investigate the thermal patterns of winter roost-sites in relation to winter ambient temperature and their insulation capacity. While tree cavities and wood stacks strongly buffered the daily cycle of temperature changes, nest boxes showed low buffering capacity. The buffering effect of tree cavities was stronger at extreme ambient temperatures compared to temperatures around zero. Heat sources inside roosts amplified Δ T (i.e., the difference between inside and outside temperatures), particularly in the closed roosts of nest boxes and tree cavities, and less in the open wood stacks with stronger circulation of air. Positive Δ T due to the installation of a heat source increased in cold ambient temperatures. These results suggest that orchard habitats in winter show a spatiotemporal mosaic of sites providing different thermal benefits varying over time and in relation to ambient temperatures. At cold temperatures tree cavities provide significantly higher thermal benefits than nest boxes or wood stacks. Thus, in winter ecology of hole-using endotherms, the availability of tree cavities may be an important characteristic of winter habitat quality.

What Is a Mild Winter? Regional Differences in Within-Species Responses to Climate Change.

PubMed

Vetter, Sebastian G; Ruf, Thomas; Bieber, Claudia; Arnold, Walter

2015-01-01

Climate change is known to affect ecosystems globally, but our knowledge of its impact on large and widespread mammals, and possibly population-specific responses is still sparse. We investigated large-scale and long-term effects of climate change on local population dynamics using the wild boar (Sus scrofa L.) as a model species. Our results show that population increases across Europe are strongly associated with increasingly mild winters, yet with region-specific threshold temperatures for the onset of exponential growth. Additionally, we found that abundant availability of critical food resources, e.g. beech nuts, can outweigh the negative effects of cold winters on population growth of wild boar. Availability of beech nuts is highly variable and highest in years of beech mast which increased in frequency since 1980, according to our data. We conclude that climate change drives population growth of wild boar directly by relaxing the negative effect of cold winters on survival and reproduction, and indirectly by increasing food availability. However, region-specific responses need to be considered in order to fully understand a species' demographic response to climate change.

Measuring facial cooling in outdoor windy winter conditions: an exploratory study.

PubMed

Briggs, Andrew G S; Gillespie, Terry J; Brown, Robert D

2017-10-01

Winter clothing provides insulation for almost all of a person's body, but in most situations, a person's face remains uncovered even in cold windy weather. This exploratory study used thermal imagery to record the rate of cooling of the faces of volunteers in a range of winter air temperatures and wind speeds. Different areas of the faces cooled at different rates with the areas around the eyes and neck cooling at the slowest rate, and the nose and cheeks cooling at the fastest rate. In all cases, the faces cooled at an approximately logarithmic decay for the first few minutes. This was followed by a small rise in the temperature of the face for a few minutes, which was then followed by an uninterrupted logarithmic decay. Volunteers were told to indicate when their face was so cold that they wanted to end the test. The total amount of time and the facial temperature at the end of each trial were recorded. The results provide insight into the way faces cool in uncontrolled, outdoor winter conditions.

Barriers to wheelchair use in the winter.

PubMed

Ripat, Jacquie D; Brown, Cara L; Ethans, Karen D

2015-06-01

To test the hypothesis that challenges to community participation posed by winter weather are greater for individuals who use scooters, manual and power wheelchairs (wheeled mobility devices [WMDs]) than for the general ambulatory population, and to determine what WMD users identify as the most salient environmental barriers to community participation during the winter. Cross-sectional survey organized around 5 environmental domains: technological, natural, physical, social/attitudinal, and policy. Urban community in Canada. Convenience sample of WMD users or their proxy (N=99). Not applicable. Not applicable. Forty-two percent identified reduced outing frequency in winter months, associated with increased age (χ(3)=6.4, P=.04), lack of access to family/friends for transportation (χ(2)=8.1, P=.04), and primary type of WMD used in the winter (scooter χ(2)=8.8, P=.003). Most reported tires/casters becoming stuck in the snow (95%) or slipping on the ice (91%), difficulty ascending inclines/ramps (92%), and cold hands while using controls or pushing rims (85%); fewer identified frozen wheelchair/scooter batteries, seat cushions/backrests, or electronics. Sidewalks/roads were reported to be problematic by 99%. Eighty percent reported needing additional help in the winter. Limited community access in winter led to a sense of loneliness/isolation, and fear/anxiety related to safety. Respondents identified policies that limited participation during winter. People who use WMDs decrease their community participation in cold weather because of multiple environmental barriers. Clinicians, researchers, and policymakers can take a multidimensional approach to mitigate these barriers in order to enhance community participation by WMD users in winter. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Tracking the delayed response of the northern winter stratosphere to ENSO using multi reanalyses and model simulations

NASA Astrophysics Data System (ADS)

Ren, Rongcai; Rao, Jian; Wu, Guoxiong; Cai, Ming

2017-05-01

The concurrent effects of the El Niño-Southern Oscillation (ENSO) on the northern winter stratosphere have been widely recognized; however, the delayed effects of ENSO in the next winter after mature ENSO have yet to be confirmed in multi reanalyses and model simulations. This study uses three reanalysis datasets, a long-term fully coupled model simulation, and a high-top general circulation model to examine ENSO's delayed effects in the stratosphere. The warm-minus-cold composite analyses consistently showed that, except those quick-decaying quasi-biennial ENSO events that reverse signs during July-August-September (JAS) in their decay years, ENSO events particularly those quasi-quadrennial (QQ) that persist through JAS, always have a significant effect on the extratropical stratosphere in both the concurrent winter and the next winter following mature ENSO. During the concurrent winter, the QQ ENSO-induced Pacific-North American (PNA) pattern corresponds to an anomalous wavenumber-1 from the upper troposphere to the stratosphere, which acts to intensify/weaken the climatological wave pattern during warm/cold ENSO. Associated with the zonally quasi-homogeneous tropical forcing in spring of the QQ ENSO decay years, there appear persistent and zonally quasi-homogeneous temperature anomalies in the midlatitudes from the upper troposphere to the lower stratosphere until summer. With the reduction in ENSO forcing and the PNA responses in the following winter, an anomalous wavenumber-2 prevails in the extratropics. Although the anomalous wave flux divergence in the upper stratospheric layer is still dominated by wavenumber-1, it is mainly caused by wavenumber-2 in the lower stratosphere. However, the wavenumber-2 activity in the next winter is always underestimated in the model simulations, and wavenumber-1 activity dominates in both winters.

Causes and Consequences of Exceptional North Atlantic Heat Loss in Recent Winters

NASA Astrophysics Data System (ADS)

Josey, Simon; Grist, Jeremy; Duchez, Aurelie; Frajka-Williams, Eleanor; Hirschi, Joel; Marsh, Robert; Sinha, Bablu

2016-04-01

The mid-high latitude North Atlantic loses large amounts of heat to the atmosphere in winter leading to dense water formation. An examination of reanalysis datasets (ERA-Interim, NCEP/NCAR) reveals that heat loss in the recent winters 2013-14 and 2014-15 was exceptionally strong. The causes and consequences of this extraordinary ocean heat loss will be discussed. In 2013-2014, the net air-sea heat flux anomaly averaged over the whole winter exceeded 100 Wm-2 in the eastern subpolar gyre (the most extreme in the period since 1979 spanned by ERA-Interim). The causes of this extreme heat loss will be shown to be severe latent and sensible heat fluxes driven primarily by anomalously strong westerly airflows from North America and northerly airflows originating in the Nordic Seas. The associated sea level pressure anomaly field reflects the dominance of the second mode of atmospheric variability, the East Atlantic Pattern (EAP) over the North Atlantic Oscillation (NAO) in this winter. The extreme winter heat loss had a significant impact on the ocean extending from the sea surface into the deeper layers and a re-emergent cold Sea Surface Temperature (SST) anomaly is evident in November 2014. The following winter 2014-15 experienced further extreme heat loss that served to amplify the strength of the re-emergent SST anomaly. By summer 2015, an unprecedented cold mid-latitude North Atlantic Ocean surface temperature anomaly is evident in observations and has been widely referred to as the 'big blue blob'. The role played by the extreme surface heat loss in the preceding winters in generating this feature and it subsequent evolution through winter 2015-16 will be explored.

Potential vorticity regimes over East Asia during winter

NASA Astrophysics Data System (ADS)

Huang, Wenyu; Chen, Ruyan; Wang, Bin; Wright, Jonathon S.; Yang, Zifan; Ma, Wenqian

2017-02-01

Nine potential vorticity (PV) regimes over East Asia are identified by applying a Self-Organizing Map and Hierarchical Ascendant Classification regime analysis to the daily PV reanalysis fields on the 300 K isentropic surface for December-March 1948-2014. According to the surface temperature anomalies over East Asia, these nine regimes are further classified into three classes, i.e., cold class (three regimes), warm class (four regimes), and neutral class (two regimes). The PV-based East Asian winter monsoon index (EAWMI) is used to study the relationship between PV distributions and the temperature anomalies. The magnitude of cold (warm) anomalies over the land areas of East Asia increases (decreases) quasi-linearly with the EAWMI. Regression analysis reveals that cold temperature anomalies preferentially occur when the EAWMI exceeds a threshold at ˜0.2 PVU (where 1 PVU ≡ 10-6 m2 K kg-1 s-1). PV inversion uncovers the mechanisms behind the relationships between the PV regimes and surface temperature anomalies and reveals that cold (warm) PV regimes are associated with significant warming (cooling) in the upper troposphere and lower stratosphere. On average, cold regimes have longer durations than warm regimes. Interclass transition probabilities are much higher for paths from warm/neutral regimes to cold regimes than for paths from cold regimes to warm/neutral regimes. Besides, intraclass transitions are rare within the warm or neutral regimes. The PV regime analysis provides insight into the causes of severe cold spells over East Asia, with blocking circulation patterns identified as the primary factor in initiating and maintaining these cold spells.

Synoptic climatological analyses on the seasonal transition from winter to spring in Europe also with attention to the day-to-day variability (Comparing with that in East Asia)

NASA Astrophysics Data System (ADS)

Kato, Kuranoshin; Hamaki, Tatsuya; Haga, Yuichi; Otani, Kazuo; Kato, Haruko

2016-04-01

There are many stages with rapid seasonal transitions in East Asia, greatly influenced by the considerable phase differences of seasonal cycle among the Asian monsoon subsystems, resulting in the variety of "seasonal feeling". The seasonal cycle has been an important background for generation of the many kinds of arts also in Europe around the western edge of the Eurasian Continent. Especially around Germany, there are so many music or literature works in which the "May" is treated as the special season. However, more detailed examination and its comparison with that in East Asia about the seasonal evolution from winter to spring including before May would be interesting. Deeper knowledge on the seasonal cycle would contribute greatly to the cultural understanding as mentioned above, as well as for considering the detailed response of the regional climate to the global-scale impacts such as the global warming. As such, the present study examined, based mainly on the NCEP/NCAR reanalysis data during 1971-2010, the synoptic climatological features on the seasonal transition from winter to spring in Europe also with attention to the day-to-day variability, by comparing with those in East Asia (detailed analyses were made mainly for 2000/01 - 2010/11 winters). Around the region from Germany to Turkey, the surface air temperature (TS) showed rather larger day-to-day variation (including the interannual or intraseasonal variation) throughout a year than in the Japan Islands area in East Asia. Especially from December to March (the minimum period of the climatological TS in the European side), the day-to-day variation was extremely great around Germany and its northern region (to the north of around 45N/10E). Thus, the extremely low temperature events sometimes appeared around Germany till the end of March, although the seasonal mean TS was not so considerably low. The day-to-day variation of sea level pressure (SLP) was also very large where such large amplitude of TS was found, although the extremely large day-to-day variation of SLP was found from the earlier season (October to March). It is interesting that the region where such large day-to-day amplitudes of TS and SLP were observed corresponded to the southeastern periphery zone of the Icelandic Low in the seasonal mean field. Besides, sub-monthly or about 30-day-period intraseasonal variation of the eastward intrusion of the Icelandic Low near the northwestern Europe was also clearly found in winter, as well as the short-period variation of the synoptic-scale disturbances to the southeast of the intraseasonal-scale Icelandic Low. In the seasonal mean field, relatively strong warm air advection in the lower layer was found to the southeast of the Icelandic Low due to combination of the strong westerly wind there and the cold air in the further eastern region. Such warm advection can be intermittently enhanced especially when the Icelandic Low intruded more closely to the northwestern Europe. These situations seem to result in the large day-to-day variation of TS around Germany and its northern region until the seasonal weakening of the Icelandic Low from March to April.

Antifreeze Proteins Modify the Freezing Process In Planta12

PubMed Central

Griffith, Marilyn; Lumb, Chelsey; Wiseman, Steven B.; Wisniewski, Michael; Johnson, Robert W.; Marangoni, Alejandro G.

2005-01-01

During cold acclimation, winter rye (Secale cereale L. cv Musketeer) plants accumulate antifreeze proteins (AFPs) in the apoplast of leaves and crowns. The goal of this study was to determine whether these AFPs influence survival at subzero temperatures by modifying the freezing process or by acting as cryoprotectants. In order to inhibit the growth of ice, AFPs must be mobile so that they can bind to specific sites on the ice crystal lattice. Guttate obtained from cold-acclimated winter rye leaves exhibited antifreeze activity, indicating that the AFPs are free in solution. Infrared video thermography was used to observe freezing in winter rye leaves. In the absence of an ice nucleator, AFPs had no effect on the supercooling temperature of the leaves. However, in the presence of an ice nucleator, AFPs lowered the temperature at which the leaves froze by 0.3°C to 1.2°C. In vitro studies showed that apoplastic proteins extracted from cold-acclimated winter rye leaves inhibited the recrystallization of ice and also slowed the rate of migration of ice through solution-saturated filter paper. When we examined the possible role of winter rye AFPs in cryoprotection, we found that lactate dehydrogenase activity was higher after freezing in the presence of AFPs compared with buffer, but the same effect was obtained by adding bovine serum albumin. AFPs had no effect on unstacked thylakoid volume after freezing, but did inhibit stacking of the thylakoids, thus indicating a loss of thylakoid function. We conclude that rye AFPs have no specific cryoprotective activity; rather, they interact directly with ice in planta and reduce freezing injury by slowing the growth and recrystallization of ice. PMID:15805474

"Cold" and "hot" thermal anomalies/events during spring and autumn in Poland

NASA Astrophysics Data System (ADS)

Graczyk, Dariusz; Szwed, Małgorzata; Choryński, Adam

2014-05-01

Regular air temperatures' changes, as an effect of succession of the seasons, are a part of people's everyday life. When winters and summers are not characterised by extreme thermal conditions, people are well prepared and there are no losses for agriculture and economy or human health consequences observed. A similar situation takes place in case of typical springs and autumns, where normally no too low or too high air temperatures occur. The situation becomes totally different when the air temperature significantly exceeds frames of typical temperature for particular months or seasons. Appearance of winter conditions during months in which they are not expected may lead to losses in different branches of the economy e.g. transport or agriculture. Heat in non-summer months potentially brings less damages for the economy, but it might be a great threat for human health, especially for those with cardiological diseases, and it may result in thermal discomfort. If these conditions last for sufficient period of time, they may cause disorders in plant vegetation cycles. One element of the discussion held on the global warming which has been observed since the half of the twentieth century, is the question of how this effects the occurrence of climatic anomalies. Does it result in an decrease of "cold" thermal anomalies and in an increase of frequency of "hot" anomalies? Or does it increase the occurrence of both types of these events? In this research there will be performed an analysis of the occurrence of conditions typical for winter months, outside the climatic winter (December, January, February) at ten locations in the area of Poland. During the months directly close to this period (November and March) the threshold for winter conditions will be maximum temperature below 0 oC which means occurrence of frost all day long. For other non-summer months the threshold will be mean daily temperature below 0 oC meaning low temperatures during the day, not only morning frosts. A similar procedure will be used for summer conditions outside the climatic summer (June, July, August), where for months close to climatic summer (May and September) the thresholds will be set at maximum temperature higher than 30 oC and 25 oC for other spring and autumn months. In order to assess if, and to what extent , the occurrence of anomalies and rare thermal events changes, their number will be compared in three sub-periods: 1951-1980; 1961-1990; 1991-2013 (the period after 1990, where warming in Poland is observed). The final stage of the analysis will be detection of trend of anomalies calculated for ten meteorological stations in the multi-year period of 1951-2013, using statistical tests in time series.

Ozone photochemistry in an oil and natural gas extraction region during winter: simulations of a snow-free season in the Uintah Basin, Utah

NASA Astrophysics Data System (ADS)

Edwards, P. M.; Young, C. J.; Aikin, K.; deGouw, J.; Dubé, W. P.; Geiger, F.; Gilman, J.; Helmig, D.; Holloway, J. S.; Kercher, J.; Lerner, B.; Martin, R.; McLaren, R.; Parrish, D. D.; Peischl, J.; Roberts, J. M.; Ryerson, T. B.; Thornton, J.; Warneke, C.; Williams, E. J.; Brown, S. S.

2013-09-01

The Uintah Basin in northeastern Utah, a region of intense oil and gas extraction, experienced ozone (O3) concentrations above levels harmful to human health for multiple days during the winters of 2009-2010 and 2010-2011. These wintertime O3 pollution episodes occur during cold, stable periods when the ground is snow-covered, and have been linked to emissions from the oil and gas extraction process. The Uintah Basin Winter Ozone Study (UBWOS) was a field intensive in early 2012, whose goal was to address current uncertainties in the chemical and physical processes that drive wintertime O3 production in regions of oil and gas development. Although elevated O3 concentrations were not observed during the winter of 2011-2012, the comprehensive set of observations tests our understanding of O3 photochemistry in this unusual emissions environment. A box model, constrained to the observations and using the near-explicit Master Chemical Mechanism (MCM) v3.2 chemistry scheme, has been used to investigate the sensitivities of O3 production during UBWOS 2012. Simulations identify the O3 production photochemistry to be highly radical limited (with a radical production rate significantly smaller than the NOx emission rate). Production of OH from O3 photolysis (through reaction of O(1D) with water vapor) contributed only 170 pptv day-1, 8% of the total primary radical source on average (primary radicals being those produced from non-radical precursors). Other radical sources, including the photolysis of formaldehyde (HCHO, 52%), nitrous acid (HONO, 26%), and nitryl chloride (ClNO2, 13%) were larger. O3 production was also found to be highly sensitive to aromatic volatile organic compound (VOC) concentrations, due to radical amplification reactions in the oxidation scheme of these species. Radical production was shown to be small in comparison to the emissions of nitrogen oxides (NOx), such that NOx acted as the primary radical sink. Consequently, the system was highly VOC sensitive, despite the much larger mixing ratio of total non-methane hydrocarbons (230 ppbv (2080 ppbC), 6 week average) relative to NOx (5.6 ppbv average). However, the importance of radical sources which are themselves derived from NOx emissions and chemistry, such as ClNO2 and HONO, make the response of the system to changes in NOx emissions uncertain. Model simulations attempting to reproduce conditions expected during snow-covered cold-pool conditions show a significant increase in O3 production, although calculated concentrations do not achieve the highest seen during the 2010-2011 O3 pollution events in the Uintah Basin. These box model simulations provide useful insight into the chemistry controlling winter O3 production in regions of oil and gas extraction.

Trends in streamflow in the Yukon River Basin from 1944 to 2005 and the influence of the Pacific Decadal Oscillation

USGS Publications Warehouse

Brabets, T.P.; Walvoord, Michelle Ann

2009-01-01

Streamflow characteristics in the Yukon River Basin of Alaska and Canada have changed from 1944 to 2005, and some of the change can be attributed to the two most recent modes of the Pacific Decadal Oscillation (PDO). Seasonal, monthly, and annual stream discharge data from 21 stations in the Yukon River Basin were analyzed for trends over the entire period of record, generally spanning 4-6 decades, and examined for differences between the two most recent modes of the PDO: cold-PDO (1944-1975) and warm-PDO (1976-2005) subsets. Between 1944 and 2005, average winter and April flow increased at 15 sites. Observed winter flow increases during the cold-PDO phase were generally limited to sites in the Upper Yukon River Basin. Positive trends in winter flow during the warm-PDO phase broadened to include stations in the Middle and Lower Yukon River drainage basins. Increases in winter streamflow most likely result from groundwater input enhanced by permafrost thawing that promotes infiltration and deeper subsurface flow paths. Increased April flow may be attributed to a combination of greater baseflow (from groundwater increases), earlier spring snowmelt and runoff, and increased winter precipitation, depending on location. Calculated deviations from long-term mean monthly discharges indicate below-average flow in the winter months during the cold PDO and above-average flow in the winter months during the warm PDO. Although not as strong a signal, results also support the reverse response during the summer months: above-average flow during the cold PDO and below-average flow during the warm PDO. Changes in the summer flows are likely an indirect consequence of the PDO, resulting from earlier spring snowmelt runoff and also perhaps increased summer infiltration and storage in a deeper active layer. Annual discharge has remained relatively unchanged in the Yukon River Basin, but a few glacier-fed rivers demonstrate positive trends, which can be attributed to enhanced glacier melting. A positive trend in annual flow during the warm PDO near the mouth of the Yukon River suggests that small increases in flow throughout the Yukon River Basin have resulted in an additive effect manifested in the downstream-most streamflow station. Many of the identified changes in streamflow patterns in the Yukon River Basin show a correlation to the PDO regime shift. This work highlights the importance of considering proximate climate forcings as well as global climate change when assessing hydrologic changes in the Arctic.

Long-term variability of dust events in Iceland (1949-2011)

NASA Astrophysics Data System (ADS)

Dagsson-Waldhauserova, P.; Arnalds, O.; Olafsson, H.

2014-12-01

The long-term frequency of atmospheric dust observations was investigated for the southern part of Iceland and interpreted together with earlier results obtained from northeastern (NE) Iceland (Dagsson-Waldhauserova et al., 2013). In total, over 34 dust days per year on average occurred in Iceland based on conventionally used synoptic codes for dust observations. However, frequent volcanic eruptions, with the re-suspension of volcanic materials and dust haze, increased the number of dust events fourfold (135 dust days annually). The position of the Icelandic Low determined whether dust events occurred in the NE (16.4 dust days annually) or in the southern (S) part of Iceland (about 18 dust days annually). The decade with the most frequent dust days in S Iceland was the 1960s, but the 2000s in NE Iceland. A total of 32 severe dust storms (visibility < 500 m) were observed in Iceland with the highest frequency of events during the 2000s in S Iceland. The Arctic dust events (NE Iceland) were typically warm, occurring during summer/autumn (May-September) and during mild southwesterly winds, while the subarctic dust events (S Iceland) were mainly cold, occurring during winter/spring (March-May) and during strong northeasterly winds. About half of the dust events in S Iceland occurred in winter or at sub-zero temperatures. A good correlation was found between particulate matter (PM10) concentrations and visibility during dust observations at the stations Vík and Stórhöfði. This study shows that Iceland is among the dustiest areas of the world and that dust is emitted year-round.

Calcium addition at the Hubbard Brook Experimental Forest increases the capacity for stress tolerance and carbon capture in red spruce (Picea rubens) trees during the cold season

Treesearch

Paul G. Schaberg; Rakesh Minocha; Stephanie Long; Joshua M. Halman; Gary J. Hawley; Christopher Eagar

2011-01-01

Red spruce (Picea rubens Sarg.) trees are uniquely vulnerable to foliar freezing injury during the cold season (fall and winter), but are also capable of photosynthetic activity if temperatures moderate. To evaluate the influence of calcium (Ca) addition on the physiology of red spruce during the cold season, we measured concentrations of foliar...

The structure and energetics of midlatitude disturbances accompanying cold-air outbreaks over East Asia

NASA Technical Reports Server (NTRS)

Lau, N.-C.; Lau, K.-M.

1984-01-01

The evolution of extratropical transient waves as they propagate eastward from the Eurasian land mass toward the Pacific during selected cold surge events in the winter Monsoon Experiment (MONEX) is studied. The outstanding cold surge episodes during MONEX are first identified, and the salient synoptic features related to these events are described using composite streamline charts. The structure of rapidly varying disturbances accompanying the cold surges and the associated energetics are examined, and the behavior of those fluctuations over relatively longer time scales is addressed.

Cold tolerance and freeze-induced glucose accumulation in three terrestrial slugs.

PubMed

Slotsbo, Stine; Hansen, Lars Monrad; Jordaens, Kurt; Backeljau, Thierry; Malmendal, Anders; Nielsen, Niels Chr; Holmstrup, Martin

2012-04-01

Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (Arion ater, Arion rufus and Arion lusitanicus) are reported. Autumn collected slugs were cold acclimated in the laboratory and subjected to freezing conditions simulating likely winter temperatures in their habitat. Slugs spontaneously froze at about -4 °C when cooled under dry conditions, but freezing of body fluids was readily induced at -1 °C when in contact with external ice crystals. All three species survived freezing for 2 days at -1 °C, and some A. rufus and A. lusitanicus also survived freezing at -2 °C. (1)H NMR spectroscopy revealed that freezing of body fluids resulted in accumulation of lactate, succinate and glucose. Accumulation of lactate and succinate indicates that ATP production occurred via fermentative pathways, which is likely a result of oxygen depletion in frozen tissues. Glucose increased from about 6 to 22 μg/mg dry tissue upon freezing in A. rufus, but less so in A. ater and A. lusitanicus. Glucose may thus act as a cryoprotectant in these slugs, although the concentrations are not as high as reported for other freeze tolerant invertebrates. Copyright © 2012 Elsevier Inc. All rights reserved.

Foliar applied abscisic acid increases 'Chardonnay' grapevines (Vitis vinifera) bud freezing tolerance during Autumn cold acclimation

USDA-ARS?s Scientific Manuscript database

Economic loss due to cold weather events is a major constraint to winegrape-related industries where extreme and/or fluctuating winter temperatures induce injury and required remedial retraining and replanting increases production costs and lowers yield and fruit quality. The purpose of this study ...

Innovative cold tolerance test for conifer seedlings

Treesearch

Peter A. Balk; Peter Bronnum; Mike Perks; Eva Stattin; Lonneke H. M. van der Geest; Monique F. van Wordragen

2007-01-01

Forest tree nurseries rely on tight scheduling of operations to deliver vital seedlings to the planting site. Cold storage is required to: (1) prevent winter damage, especially in container seedlings; (2) to maintain planting stock in an inactive condition; and (3) to ensure plant supply for geographically distinct planting sites, a definite requirement for large-scale...

Meteorological Conditions for Functioning Automobile Transport in Moscow Region

NASA Astrophysics Data System (ADS)

Shiryaeva, Alexandra

2017-04-01

The purpose of this study is to investigate weather and climate conditions of functioning automobile transport in Moscow region. For this, statistics on the daily number of accidents in the City of Moscow in 2013-2014 were studied and compared with the weather conditions. Various weather phenomena and meteorological parameters that affect the increase and decrease in the number of accidents in warm and cold seasons were identified; the extent of this influence was assessed. Moreover, an analysis of the distribution and change of the frequency of occurrence of these phenomena and meteorological parameters in 1961-2010 in Moscow region was conducted. In the cold season, there are much more weather events influencing the growth in the number of accidents than in the warm season. Fallout of more than 2 cm of snow per date, the reduction in meteorological visibility, drizzle and snow storms lead to an increase of accident rate by 5-15%. In the warm season, when thunderstorms and heavy rainfall there is a decrease in accidents; increase in the number of accidents happens in hot weather (maximum air temperatures over +30 °C). In the period 1991-2010 compared to 1961-1990 in the Moscow oblast the sustained cold period and amount of precipitation under negative air temperature has reduced; a decrease in the number of days with reduced visibility range and the offset of the date of the fallout of the first snow aside winter months is observed, which is favorable for automobile transport. At the same time, there is an increase in the number of days with transitions of air temperature through 0 °C, and the number of hot days, which negatively affects the functioning automobile transport.

The influence of vernalization and daylength on expression of flowering-time genes in the shoot apex and leaves of barley (Hordeum vulgare).

PubMed Central

Sasani, Shahryar; Hemming, Megan N.; Oliver, Sandra N.; Greenup, Aaron; Tavakkol-Afshari, Reza; Mahfoozi, Siroos; Poustini, Kazem; Sharifi, Hamid-Reza; Dennis, Elizabeth S.; Peacock, W. James; Trevaskis, Ben

2009-01-01

Responses to prolonged low-temperature treatment of imbibed seeds (vernalization) were examined in barley (Hordeum vulgare). These occurred in two phases: the perception of prolonged cold, which occurred gradually at low temperatures, and the acceleration of reproductive development, which occurred after vernalization. Expression of the VERNALIZATION1 gene (HvVRN1) increased gradually in germinating seedlings during vernalization, both at the shoot apex and in the developing leaves. This occurred in darkness, independently of VERNALIZATION2 (HvVRN2), consistent with the hypothesis that expression of HvVRN1 is induced by prolonged cold independently of daylength flowering-response pathways. After vernalization, expression of HvVRN1 was maintained in the shoot apex and leaves. This was associated with accelerated inflorescence initiation and with down-regulation of HvVRN2 in the leaves. The largest determinant of HvVRN1 expression levels in vernalized plants was the length of seed vernalization treatment. Daylength did not influence HvVRN1 expression levels in shoot apices and typically did not affect expression in leaves. In the leaves of plants that had experienced a saturating seed vernalization treatment, expression of HvVRN1 was higher in long days, however. HvFT1 was expressed in the leaves of these plants in long days, which might account for the elevated HvVRN1 expression. Long-day up-regulation of HvVRN1 was not required for inflorescence initiation, but might accelerate subsequent stages of inflorescence development. Similar responses to seed vernalization were also observed in wheat (Triticum aestivum). These data support the hypothesis that VRN1 is induced by cold during winter to promote spring flowering in vernalization-responsive cereals. PMID:19357429

Nitrogen and phosphorus transport between Fourleague Bay, LA, and the Gulf of Mexico: The role of winter cold fronts and Atchafalaya River discharge

USGS Publications Warehouse

Perez, B.C.; Day, J.W.; Justic, D.; Twilley, R.R.

2003-01-01

Nutrient fluxes were measured between Fourleague Bay, a shallow Louisiana estuary, and the Gulf of Mexico every 3 h between February 1 and April 30, 1994 to determine how high velocity winds associated with cold fronts and peak Atchafalaya River discharge influenced transport. Net water fluxes were ebb-dominated throughout the study because of wind forcing and high volumes of water entering the northern Bay from the Atchafalaya River. Flushing time of the Bay averaged <8 days; however, more rapid flushing occurred in response to northerly winds with approximately 56% of the volume of the Bay exported to the Gulf in 1 day during the strongest flushing event. Higher nitrate + nitrite (NO2+ NO3), total nitrogen (TN), and total phosphorus (TP) concentrations were indicative of Atchafalaya River input and fluxes were greater when influenced by high velocity northerly winds associated with frontal passage. Net exports of NO2 + NO3, TN, and TP were 43.5, 98.5, and 13.6 g s-1, respectively, for the 89-day study. An average of 10.6 g s-1 of ammonium (NH4) was exported to the Gulf over the study; however, concentrations were lower when associated with riverine influence and wind-driven exports suggesting the importance of biological processes. Phosphate (PO4) fluxes were nearly balanced over the study with fairly stable concentrations indicating a well-buffered system. The results indicate that the high energy subsidy provided by natural pulsing events such as atmospheric cold fronts and seasonal river discharge are efficient mechanisms of nutrient delivery to adjacent wetlands and nearshore coastal ecosystems and are important in maintaining coastal sustainability. ?? 2003 Elsevier Ltd. All rights reserved.

Backscatter for Ice Sheet 2 Growth Phase in the Winter 1994 Winter Sea Ice Experiment

NASA Technical Reports Server (NTRS)

Nghiem, S. V.

1996-01-01

None. This is raw data from a data set taken during the CRRELEX94 experiment. The data are polarimetric C-band radar measurements of a saline ice sheet grown in the outdoor Geophysical Research Facility at the Cold Regions Research and Engineering Lab. See references for other descriptions of data.

Role of Acclimatization in Weather-Related Human Mortality During the Transition Seasons of Autumn and Spring in a Thermally Extreme Mid-Latitude Continental Climate

PubMed Central

de Freitas, Christopher R.; Grigorieva, Elena A.

2015-01-01

Human mortality is closely related to natural climate-determined levels of thermal environmental stress and the resulting thermophysiological strain. Most climate-mortality research has focused on seasonal extremes during winter and summer when mortality is the highest, while relatively little attention has been paid to mortality during the transitional seasons of autumn and spring. The body acclimatizes to heat in the summer and cold in winter and readjusts through acclimatization during the transitions between the two during which time the body experiences the thermophysiological strain of readjustment. To better understand the influences of weather on mortality through the acclimatization process, the aim here is to examine the periods that link very cold and very warms seasons. The study uses the Acclimatization Thermal Strain Index (ATSI), which is a comparative measure of short-term thermophysiological impact on the body. ATSI centers on heat exchange with the body’s core via the respiratory system, which cannot be protected. The analysis is based on data for a major city in the climatic region of the Russian Far East characterized by very hot summers and extremely cold winters. The results show that although mortality peaks in winter (January) and is at its lowest in summer (August), there is not a smooth rise through autumn nor a smooth decline through spring. A secondary peak occurs in autumn (October) with a smaller jump in May. This suggests the acclimatization from warm-to-cold produces more thermophysiological strain than the transition from cold-to-warm. The study shows that ATSI is a useful metric for quantifying the extent to which biophysical adaptation plays a role in increased strain on the body during re-acclimatization and for this reason is a more appropriate climatic indictor than air temperature alone. The work gives useful bioclimatic information on risks involved in transitional seasons in regions characterized by climatic extremes. This could be handy in planning and managing health services to the public and measures that might be used to help mitigate impacts. PMID:26703633

Role of Acclimatization in Weather-Related Human Mortality During the Transition Seasons of Autumn and Spring in a Thermally Extreme Mid-Latitude Continental Climate.

PubMed

de Freitas, Christopher R; Grigorieva, Elena A

2015-11-26

Human mortality is closely related to natural climate-determined levels of thermal environmental stress and the resulting thermophysiological strain. Most climate-mortality research has focused on seasonal extremes during winter and summer when mortality is the highest, while relatively little attention has been paid to mortality during the transitional seasons of autumn and spring. The body acclimatizes to heat in the summer and cold in winter and readjusts through acclimatization during the transitions between the two during which time the body experiences the thermophysiological strain of readjustment. To better understand the influences of weather on mortality through the acclimatization process, the aim here is to examine the periods that link very cold and very warms seasons. The study uses the Acclimatization Thermal Strain Index (ATSI), which is a comparative measure of short-term thermophysiological impact on the body. ATSI centers on heat exchange with the body’s core via the respiratory system, which cannot be protected. The analysis is based on data for a major city in the climatic region of the Russian Far East characterized by very hot summers and extremely cold winters. The results show that although mortality peaks in winter (January) and is at its lowest in summer (August), there is not a smooth rise through autumn nor a smooth decline through spring. A secondary peak occurs in autumn (October) with a smaller jump in May. This suggests the acclimatization from warm-to-cold produces more thermophysiological strain than the transition from cold-to-warm. The study shows that ATSI is a useful metric for quantifying the extent to which biophysical adaptation plays a role in increased strain on the body during re-acclimatization and for this reason is a more appropriate climatic indictor than air temperature alone. The work gives useful bioclimatic information on risks involved in transitional seasons in regions characterized by climatic extremes. This could be handy in planning and managing health services to the public and measures that might be used to help mitigate impacts.

A 500 year seasonally resolved δ18O and δ13C, layer thickness and calcite fabric record from a speleothem deposited in equilibrium of the Han-sur-Lesse cave, Belgium

NASA Astrophysics Data System (ADS)

Van Rampelbergh, M.; Verheyden, S.; Allan, M.; Quinif, Y.; Cheng, H.; Edwards, L.; Keppens, E.; Claeys, P.

2014-10-01

Speleothem δ18O and δ13C signals have already proven to enable climate reconstructions at high resolution. However, seasonally resolved speleothem records are still scarce and often difficult to interpret in terms of climate due to the multitude of factors that can affect the proxy signals. In this paper, a fast growing (up to 2 mm yr-1) seasonally laminated speleothem from the Han-sur-Lesse cave (Belgium) is analyzed for its δ18O and δ13C values, layer thickness and changes in calcite fabric. The studied part of the speleothem covers the most recent 500 years as indicated by layer counting and confirmed by 20 U/Th-ages. Epikarst recharge occurs mainly in winter and lesser during spring and fall. a good correlation can be established between lower winter temperatures and lower winter precipitation (DJF) based on the measured data by the Belgian meteorological institute since 1833 indicating that a dry winter is also a cold winter. Colder and dryer winters cause lower winter recharge and generally drier conditions in the cave. Lower winter recharge decreases the amount of isotopically light (δ18O) winter precipitation added to the epikarst in comparison to the heavier spring and fall waters, which leads to a net increase in δ18O value of the water in the epikarst. Increased δ18O values in the Proserpine are consequently interpreted to reflect colder and dryer winters. Higher δ13C signals are interpreted to reflect increased prior calcite precipitation (PCP) due to colder and dryer winters, when recharge is lower. Thinner layers and darker calcite relate to slower growth and occur when drip rates are low and when the drip water calcium ion concentration is low due to increased PCP, both caused by lower recharge during periods with colder and dryer winters. Exceptionally cold and dry winters cause the drip discharge to decrease under a certain threshold value inducing anomalies in the measured proxy records. Such anomalies occur from 1565 to 1610, from 1770 to 1800, from 1810 to 1860 and from 1880 to 1895 and correspond with exceptionally cold periods in proxy-based, historical and instrumental records and may relate to different factors such as negative winter NAO phases, lower solar irradiance and/or volcanic eruptions. When the discharge threshold is not reached, lower amplitude variations are observed such as between 1479 and 1565 and between 1730 and 1770 with two periods of relatively warmer and wetter winters. Between 1610 and 1730 a period of relatively cooler and dryer winters occurs and may relate to a decrease in solar irradiance during the Maunder Minimum (1640-1714). Seasonal δ18O variations indicate a 2.5 °C seasonality in cave air temperature during the two periods with warmer and wetter winters (1479-1565 and 1730-1770), and correspond to the cave air temperature seasonality observed today. a smaller 1.5 °C seasonality in cave air temperature occurs during the interval with colder and wetter winters between 1610 and 1730 and suggests colder summers. The δ13C seasonal changes suggest that the seasonality in discharge was lower than the one observed today with a short interval of increased seasonality between 1600 and 1660 reflecting stronger summer PCP-effects due to decreased winter recharge.

Episodes of clinical mastitis and its relationship with duration of treatment and seasonality in crossbred cows maintained in organized dairy farm

PubMed Central

Kumar, Narender; Manimaran, A.; Kumaresan, A.; Sreela, L.; Patbandha, Tapas Kumar; Tiwari, Shiwani; Chandra, Subhash

2016-01-01

Aim: Present study aimed to evaluate the different episodes of clinical mastitis (CM) and influence of duration of treatment and seasonality on the occurrence of different episodes of CM in crossbred cows. Materials and Methods: A total of 1194 lactation data of crossbred CM cows were collected from mastitis treatment record from 2002 to 2012. Data of CM cows were classified into types of episodes (pattern of repeated or multiple episodes occurrence) and number of episodes (magnitude of multiple cases). Types of episodes were divided as single (clinical cure by a single episode of treatment), relapse (retreatment of the same cow within 21 days), recurrence (new CM at least 21 days after treatment), and both (relapse and recurrence). The season was classified as winter (December to March), summer (April to June), rainy (July to September), and autumn (October to November). The difference between incidences of different types of CM episodes and the association between number or type of CM episodes with duration of treatment and seasons of CM occurrence were analyzed by Chi-square test. Results: Among 1194 animals suffered with CM, 53, 16, and 18% had the single episode, relapse, and recurrence, respectively; while 13% suffered by both relapse and recurrence. We estimated the duration of treatment and found 80% of the cows treated 1-8 days, in which 65% treated for 1-4 days, while 35% cows were treated for 5-8 days. Further, 12% cows treated for 9-15 days and 7.5% cows treated >15 days. The relationship between duration of treatment and different episodes of CM revealed that 1-8 days treated cows were mostly cured by the single episode with less relapse and recurrence. In contrast, the incidences of recurrence and relapse episodes were higher in cows treated for more than 9 days. The highest incidence of relapse was noticed in winter (36%) than other seasons (10-28%), while the recurrence was less during autumn (9%) compared to other seasons (20-40%). Conclusion: Cows those suffered by both relapse and recurrence were more susceptible to CM, and they need to be culled from farm to control the transmission of infections. Although the influence of seasonality was difficult to understand, the higher magnitude of relapse and recurrence during winter suggested the adverse effects of cold stress on treatment outcome. PMID:27051189

Episodes of clinical mastitis and its relationship with duration of treatment and seasonality in crossbred cows maintained in organized dairy farm.

PubMed

Kumar, Narender; Manimaran, A; Kumaresan, A; Sreela, L; Patbandha, Tapas Kumar; Tiwari, Shiwani; Chandra, Subhash

2016-01-01

Present study aimed to evaluate the different episodes of clinical mastitis (CM) and influence of duration of treatment and seasonality on the occurrence of different episodes of CM in crossbred cows. A total of 1194 lactation data of crossbred CM cows were collected from mastitis treatment record from 2002 to 2012. Data of CM cows were classified into types of episodes (pattern of repeated or multiple episodes occurrence) and number of episodes (magnitude of multiple cases). Types of episodes were divided as single (clinical cure by a single episode of treatment), relapse (retreatment of the same cow within 21 days), recurrence (new CM at least 21 days after treatment), and both (relapse and recurrence). The season was classified as winter (December to March), summer (April to June), rainy (July to September), and autumn (October to November). The difference between incidences of different types of CM episodes and the association between number or type of CM episodes with duration of treatment and seasons of CM occurrence were analyzed by Chi-square test. Among 1194 animals suffered with CM, 53, 16, and 18% had the single episode, relapse, and recurrence, respectively; while 13% suffered by both relapse and recurrence. We estimated the duration of treatment and found 80% of the cows treated 1-8 days, in which 65% treated for 1-4 days, while 35% cows were treated for 5-8 days. Further, 12% cows treated for 9-15 days and 7.5% cows treated >15 days. The relationship between duration of treatment and different episodes of CM revealed that 1-8 days treated cows were mostly cured by the single episode with less relapse and recurrence. In contrast, the incidences of recurrence and relapse episodes were higher in cows treated for more than 9 days. The highest incidence of relapse was noticed in winter (36%) than other seasons (10-28%), while the recurrence was less during autumn (9%) compared to other seasons (20-40%). Cows those suffered by both relapse and recurrence were more susceptible to CM, and they need to be culled from farm to control the transmission of infections. Although the influence of seasonality was difficult to understand, the higher magnitude of relapse and recurrence during winter suggested the adverse effects of cold stress on treatment outcome.

Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study.

PubMed

Palacios, C; Abecia, J A

2015-05-01

A total number of 48,088 artificial inseminations (AIs) have been controlled during seven consecutive years in 79 dairy sheep Spanish farms (41° N). Mean, maximum and minimum ambient temperatures (Ts), temperature amplitude (TA), mean relative humidity (RH), mean solar radiation (SR) and total rainfall of each insemination day and 15 days later were recorded. Temperature-humidity index (THI) and effective temperature (ET) have been calculated. A binary logistic regression model to estimate the risk of not getting pregnant compared to getting pregnant, through the odds ratio (OR), was performed. Successful winter inseminations were carried out under higher SR (P < 0.01) and summer inseminations under lower SR values (P < 0.05). Successful inseminations during the summer were performed under significantly lower maximum T (P < 0.01), while winter inseminations resulted in pregnancy when they were carried out under higher maximum (P < 0.05) and minimum Ts (P < 0.01). Up to five meteorological variables presented OR >1 (maximum T, ET and rainfall on AI day, and ET and rainfall on day 15), and two variables presented OR <1 (SR on AI day and maximum T on day 15). However, the effect of meteorological factors affected fertility in opposite ways, so T becomes a protective or risk factor on fertility depending on season. In conclusion, the percentage of pregnancy after AI in sheep is significantly affected by meteorological variables in a seasonal-dependent manner, so the parameters such as temperature reverse their effects in the hot or cold seasons. A forecast of the meteorological conditions could be a useful tool when AI dates are being scheduled.

Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study

NASA Astrophysics Data System (ADS)

Palacios, C.; Abecia, J. A.

2015-05-01

A total number of 48,088 artificial inseminations (AIs) have been controlled during seven consecutive years in 79 dairy sheep Spanish farms (41° N). Mean, maximum and minimum ambient temperatures ( Ts), temperature amplitude (TA), mean relative humidity (RH), mean solar radiation (SR) and total rainfall of each insemination day and 15 days later were recorded. Temperature-humidity index (THI) and effective temperature (ET) have been calculated. A binary logistic regression model to estimate the risk of not getting pregnant compared to getting pregnant, through the odds ratio (OR), was performed. Successful winter inseminations were carried out under higher SR ( P < 0.01) and summer inseminations under lower SR values ( P < 0.05). Successful inseminations during the summer were performed under significantly lower maximum T ( P < 0.01), while winter inseminations resulted in pregnancy when they were carried out under higher maximum ( P < 0.05) and minimum Ts ( P < 0.01). Up to five meteorological variables presented OR >1 (maximum T, ET and rainfall on AI day, and ET and rainfall on day 15), and two variables presented OR <1 (SR on AI day and maximum T on day 15). However, the effect of meteorological factors affected fertility in opposite ways, so T becomes a protective or risk factor on fertility depending on season. In conclusion, the percentage of pregnancy after AI in sheep is significantly affected by meteorological variables in a seasonal-dependent manner, so the parameters such as temperature reverse their effects in the hot or cold seasons. A forecast of the meteorological conditions could be a useful tool when AI dates are being scheduled.

Nonshivering thermogenesis and adaptation to fasting in king penguin chicks.

PubMed

Duchamp, C; Barre, H; Delage, D; Rouanet, J L; Cohen-Adad, F; Minaire, Y

1989-10-01

The ability to develop nonshivering thermogenesis (NST) and the effect of fasting on thermogenic response to cold were studied in winter-acclimatized king penguin chicks. Metabolic rate (MR) and integrated electrical muscle activity were measured at different ambient temperatures. In cold-acclimatized (5 degrees C) fed chicks, shivering threshold temperature (STT) was 9.4 degrees C lower than lower critical temperature (LCT), indicating that NST (0.7 W/kg) occurs at moderate cold, whereas in control chicks fed and reared at 25 degrees C for 3 wk, LCT and STT were similar. Chicks reared in the cold and fasting for 3 wk or 4-5 mo (natural winter fast) developed an NST of 0.8 and 2.4 W/kg, respectively, despite the fast. In fasting chicks, the intercept of the metabolic curve with the abscissa at zero MR was far below body temperature, contrasting with the classic model for heat loss. Their low LCT indicates the capacity of a large reduction in convective conductance characteristic of diving animals and allows energy sparing in moderate cold. Below LCT, conductance reincreases progressively, leading to a steeper than expected slope of the metabolic curve and allowing preservation of a threshold temperature in the shell. These results show for the first time in a wild young bird the development of NST after cold acclimatization. Further, at the temperature of cold acclimatization, an energy-sparing mechanism is shown in response to long-term fast adaptation.

Strategic Studies Quarterly (SSQ). Volume 11, Number 1. Spring 2017

DTIC Science & Technology

2017-04-01

tour of the strategic horizon, noting the characteristics, proponents, and critics of each approach. The debate over grand strategy is a post –Cold...Winter 1996 issue of International Security.5 There, the authors sug- gested four rival grand strategies that might guide American post –Cold War...primacy the adopted grand strategy of the US government during the post –Cold War period? To some degree it was, although not to the extent that its

Thermodynamic and dynamic structure of atmosphere over the east coast of Peninsular Malaysia during the passage of a cold surge

NASA Astrophysics Data System (ADS)

Samah, Azizan Abu; Babu, C. A.; Varikoden, Hamza; Jayakrishnan, P. R.; Hai, Ooi See

2016-08-01

An intense field observation was carried out for a better understanding of cold surge features over Peninsular Malaysia during the winter monsoon season. The study utilizes vertical profiles of temperature, humidity and wind at high vertical and temporal resolution over Kota Bharu, situated in the east coast of Peninsular Malaysia. LCL were elevated during the passage of the cold surge as the relative humidity values decreased during the passage of cold surge. Level of Free Convection were below 800 hPa and equilibrium levels were close to the LFC in most of the cases. Convective available potential energy and convection inhibition energy values were small during most of the observations. Absence of local heating and instability mechanism are responsible for the peculiar thermodynamic structure during the passage of the cold surge. The wind in the lower atmosphere became northeasterly and was strong during the entire cold surge period. A slight increase in temperature near the surface and a drop in temperature just above the surface were marked by the passage of the cold surge. A remarkable increase in specific humidity was observed between 970 and 900 hPa during the cold surge period. Further, synoptic scale features were analyzed to identify the mechanism responsible for heavy rainfall. Low level convergence, upper level divergence and cyclonic vorticity prevailed over the region during the heavy rainfall event. Dynamic structure of the atmosphere as part of the organized convection associated with the winter monsoon was responsible for the vertical lifting and subsequent rainfall.

Seasonal variation in body mass, body temperature and thermogenesis in the Hwamei, Garrulax canorus.

PubMed

Wu, Mei-Xiu; Zhou, Li-Meng; Zhao, Li-Dan; Zhao, Zhi-Jun; Zheng, Wei-Hong; Liu, Jin-Song

2015-01-01

The basal thermogenesis of birds is beginning to be viewed as a highly flexible physiological trait influenced by environmental fluctuations, particularly changes in ambient temperature (Ta). Many birds living in regions with seasonal fluctuations in Ta typically respond to cold by increasing their insulation and adjusting their metabolic rate. To understand these metabolic adaptations, body temperature (Tb), metabolic rate (MR), thermal neutral zone (TNZ) and thermal conductance were measured within a range of temperatures from 5 to 40°C in free-living Hwamei, Garrulax canorus, in both winter and summer. Body mass was 61.2±0.3g in winter and 55.5±1.0g in summer, and mean Tb was 41.6±0.1°C in winter and 42.3±0.1°C in summer. TNZ was between 28.3 and 35.1°C in winter and between 28.7 and 33.2°C in summer. The mean basal metabolic rate (BMR) within TNZ was 203.32±11.81ml O2 h(-1) in winter and 168.99±6.45ml O2 h(-1) in summer. Minimum thermal conductance was 3.73±0.09joulesg(-1)h(-1)°C(-1) in winter and 3.26±0.06joulesg(-1)h(-1)°C(-1) in summer. Birds caught in winter had higher body mass, MR, and more variable TNZ than those in summer. The increased winter BMR indicates improved ability to cope with cold and maintenance of a high Tb. These results show that the Hwamei's metabolism is not constant, but exhibits pronounced seasonal phenotypic flexibility associated with maintenance of a high Tb. Copyright © 2014 Elsevier Inc. All rights reserved.

Subseasonal Reversal of East Asian Surface Temperature Variability in Winter 2014/15

NASA Astrophysics Data System (ADS)

Xu, Xinping; Li, Fei; He, Shengping; Wang, Huijun

2018-06-01

Although there has been a considerable amount of research conducted on the East Asian winter-mean climate, subseasonal surface air temperature (SAT) variability reversals in the early and late winter remain poorly understood. In this study, we focused on the recent winter of 2014/15, in which warmer anomalies dominated in January and February but colder conditions prevailed in December. Moreover, Arctic sea-ice cover (ASIC) in September-October 2014 was lower than normal, and warmer sea surface temperature (SST) anomalies occurred in the Niño4 region in winter, together with a positive Pacific Decadal Oscillation (PDO|+) phase. Using observational data and CMIP5 historical simulations, we investigated the PDO|+ phase modulation upon the winter warm Niño4 phase (autumn ASIC reduction) influence on the subseasonal SAT variability of East Asian winter. The results show that, under a PDO|+ phase modulation, warm Niño4 SST anomalies are associated with a subseasonal delay of tropical surface heating and subsequent Hadley cell and Ferrel cell intensification in January-February, linking the tropical and midlatitude regions. Consistently, the East Asian jet stream (EAJS) is significantly decelerated in January-February and hence promotes the warm anomalies over East Asia. Under the PDO|+ phase, the decrease in ASIC is related to cold SST anomalies in the western North Pacific, which increase the meridional temperature gradient and generate an accelerated and westward-shifted EAJS in December. The westward extension of the EAJS is responsible for the eastward-propagating Rossby waves triggered by declining ASIC and thereby favors the connection between ASIC and cold conditions over East Asia.

Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.

PubMed

Bokhorst, Stef; Bjerke, Jarle W; Davey, Matthew P; Taulavuori, Kari; Taulavuori, Erja; Laine, Kari; Callaghan, Terry V; Phoenix, Gareth K

2010-10-01

Insulation provided by snow cover and tolerance of freezing by physiological acclimation allows Arctic plants to survive cold winter temperatures. However, both the protection mechanisms may be lost with winter climate change, especially during extreme winter warming events where loss of snow cover from snow melt results in exposure of plants to warm temperatures and then returning extreme cold in the absence of insulating snow. These events cause considerable damage to Arctic plants, but physiological responses behind such damage remain unknown. Here, we report simulations of extreme winter warming events using infrared heating lamps and soil warming cables in a sub-Arctic heathland. During these events, we measured maximum quantum yield of photosystem II (PSII), photosynthesis, respiration, bud swelling and associated bud carbohydrate changes and lipid peroxidation to identify physiological responses during and after the winter warming events in three dwarf shrub species: Empetrum hermaphroditum, Vaccinium vitis-idaea and Vaccinium myrtillus. Winter warming increased maximum quantum yield of PSII, and photosynthesis was initiated for E. hermaphroditum and V. vitis-idaea. Bud swelling, bud carbohydrate decreases and lipid peroxidation were largest for E. hermaphroditum, whereas V. myrtillus and V. vitis-idaea showed no or less strong responses. Increased physiological activity and bud swelling suggest that sub-Arctic plants can initiate spring-like development in response to a short winter warming event. Lipid peroxidation suggests that plants experience increased winter stress. The observed differences between species in physiological responses are broadly consistent with interspecific differences in damage seen in previous studies, with E. hermaphroditum and V. myrtillus tending to be most sensitive. This suggests that initiation of spring-like development may be a major driver in the damage caused by winter warming events that are predicted to become more frequent in some regions of the Arctic and that may ultimately drive plant community shifts. Copyright © Physiologia Plantarum 2010.

Overexpression of DEMETER, a DNA demethylase, promotes early apical bud maturation in poplar.

PubMed

Conde, Daniel; Moreno-Cortés, Alicia; Dervinis, Christopher; Ramos-Sánchez, José M; Kirst, Matias; Perales, Mariano; González-Melendi, Pablo; Allona, Isabel

2017-11-01

The transition from active growth to dormancy is critical for the survival of perennial plants. We identified a DEMETER-like (CsDML) cDNA from a winter-enriched cDNA subtractive library in chestnut (Castanea sativa Mill.), an economically and ecologically important species. Next, we characterized this DNA demethylase and its putative ortholog in the more experimentally tractable hybrid poplar (Populus tremula × alba), under the signals that trigger bud dormancy in trees. We performed phylogenetic and protein sequence analysis, gene expression profiling, and 5-methyl-cytosine methylation immunodetection studies to evaluate the role of CsDML and its homolog in poplar, PtaDML6. Transgenic hybrid poplars overexpressing CsDML were produced and analysed. Short days and cold temperatures induced CsDML and PtaDML6. Overexpression of CsDML accelerated short-day-induced bud formation, specifically from Stages 1 to 0. Buds acquired a red-brown coloration earlier than wild-type plants, alongside with the up-regulation of flavonoid biosynthesis enzymes and accumulation of flavonoids in the shoot apical meristem and bud scales. Our data show that the CsDML gene induces bud formation needed for the survival of the apical meristem under the harsh conditions of winter. © 2017 John Wiley & Sons Ltd.

Effects of chronic N fertilization on foliar membranes, cold tolerance, and carbon storage in montane red spruce

Treesearch

Paul G. Schaberg; Donald H. DeHayes; Gary J. Hawley; Paula F. Murakami; G. Richard Strimbeck; Steven G. McNulty

2002-01-01

We evaluated the influence of protracted low-level nitrogen (N) fertilization on foliar membrane-associated calcium (mCa), sugar and starch concentrations, membrane stability, winter cold tolerance, and freezing injury of red spruce (Picea rubens Sarg.) trees growing in six experimental plots on Mount Ascutney, Vermont. For 12 consecutive years...

Nordic Winter and Cold: Their Correspondence with Tomas Tranströmer's Poetry

ERIC Educational Resources Information Center

Hosian, Mohammad Akbar

2015-01-01

The Nobel Prize winning poet Tomas Tranströmer was born and bred in Sweden, a remarkably Scandinavian country. Topographically, Scandinavian countries are locations of extreme cold and snowing. This distinguishing climatic condition has had a dominant influence and impact on almost all Scandinavian art and literature, including Tomas Tranströmer's…

78 FR 17178 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Shrimp Fishery Off the Southern...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-20

... waters close as a result of severe winter weather. Amendment 9 would also revise the overfished and... has been severely depleted by cold weather. Based on information from standardized assessments, if a... changes to the current regulatory text within Sec. 622.35(d), ``South Atlantic shrimp cold weather closure...

Situation Climatic Briefs

DTIC Science & Technology

1982-09-01

F-7 CHILE -ARGENTINA SOUTH OF 40 DEGREES SOUTH .... ............. .. F-13 CHILE -PERU BORDER ................. ......................... F...34SITUATION CLIMATIC BRIEF CHILE -ARGENTINA SOUTH OF 40 DEGREES SOUTH ANNUAL 1. GENERAL. The weather is generally cloudy, windy, and cold year-round...conditions can occur for 3 or 4 hours following cold frontal passage during the winter. 4. TERMINAL WEATHER. Puerto Montt, Chile . Fair. Conditions are

Modulations of aerosol impacts on cloud microphysics induced by the warm Kuroshio Current under the East Asian winter monsoon

NASA Astrophysics Data System (ADS)

Koike, M.; Asano, N.; Nakamura, H.; Sakai, S.; Nagao, T. M.; Nakajima, T. Y.

2016-10-01

In our previous aircraft observations, the possible influence of high sea surface temperature (SST) along the Kuroshio Current on aerosol-cloud interactions over the western North Pacific was revealed. The cloud droplet number concentration (Nc) was found to increase with decreasing near-surface static stability (NSS), which was evaluated locally as the difference between the SST and surface air temperature (SAT). To explore the spatial and temporal extent to which this warm SST influence can be operative, the present study analyzed Nc values estimated from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite measurements. The comparison of the local Nc values between the high and low SST - SAT days revealed a marked increase in Nc (up to a factor of 1.8) along the Kuroshio Current in the southern East China Sea, where particularly high SST - SAT values (up to 8 K) were observed in winter under monsoonal cold air outflows from the Asian Continent. This cold airflow destabilizes the atmospheric boundary layer, which leads to enhanced updraft velocities within the well-developed mixed layer and thus greater Nc. The monsoonal northwesterlies also bring a large amount of anthropogenic aerosols from the Asian continent that increase Nc in the first place. These results suggest that the same modulations of cloud microphysics can occur over other warm western boundary currents, including the Gulf Stream, under polluted cool continental airflows. Possibilities of influencing the cloud liquid water path are also discussed.

Relationships between teleconnection patterns and Turkish climatic extremes

NASA Astrophysics Data System (ADS)

Baltacı, H.; Akkoyunlu, B. O.; Tayanç, M.

2017-12-01

This is a study on the effects of teleconnection patterns (TPs) on the extremes of temperature and precipitation over Turkey. Relationships between five teleconnection patterns, North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East Atlantic-Western Russia (EAWR), East Atlantic (EA), and Scandinavian (SCA) patterns, and 11 climate extreme indices were studied by using 94 uniformly distributed meteorological stations over Turkey for the period of 1965-2014. Analyzing strong positive and negative temperature deviations from the 50-year-winter means shows that such extremes can often be explained by using AO and EAWR patterns. During the negative AO, generally more warm days occur over Black Sea (r = -0.6) and Aegean regions (r = -0.7). This phase of AO also generates above-normal precipitation in the western parts of the Anatolian Peninsula (r around - 0.5). Winter-time negative AO is mainly associated with the presence of a deepened Genoa cyclone over Italy that can transport warm and moist air mass from Mediterranean Sea towards Turkey by strong westerly winds. In contrast, positive EAWR is mainly connected to cold nights over Black Sea (r = 0.6) and Aegean regions (r = 0.6) together with positive precipitation anomalies at the seaside stations of the eastern Black Sea region. On the other hand, when positive EAWR prevails, Azores high-pressure center expands towards continental Europe bringing cold air by strong northerly winds together with higher moisture transport from the Black Sea. These results could pave the way for new possibilities regarding the projection of extremes in downscaling techniques.

Covariability of seasonal temperature and precipitation over the Iberian Peninsula in high-resolution regional climate simulations (1001-2099)

NASA Astrophysics Data System (ADS)

Fernández-Montes, S.; Gómez-Navarro, J. J.; Rodrigo, F. S.; García-Valero, J. A.; Montávez, J. P.

2017-04-01

Precipitation and surface temperature are interdependent variables, both as a response to atmospheric dynamics and due to intrinsic thermodynamic relationships and feedbacks between them. This study analyzes the covariability of seasonal temperature (T) and precipitation (P) across the Iberian Peninsula (IP) using regional climate paleosimulations for the period 1001-1990, driven by reconstructions of external forcings. Future climate (1990-2099) was simulated according to SRES scenarios A2 and B2. These simulations enable exploring, at high spatial resolution, robust and physically consistent relationships. In winter, positive P-T correlations dominate west-central IP (Pearson correlation coefficient ρ = + 0.43, for 1001-1990), due to prevalent cold-dry and warm-wet conditions, while this relationship weakens and become negative towards mountainous, northern and eastern regions. In autumn, negative correlations appear in similar regions as in winter, whereas for summer they extend also to the N/NW of the IP. In spring, the whole IP depicts significant negative correlations, strongest for eastern regions (ρ = - 0.51). This is due to prevalent frequency of warm-dry and cold-wet modes in these regions and seasons. At the temporal scale, regional correlation series between seasonal anomalies of temperature and precipitation (assessed in 31 years running windows in 1001-1990) show very large multidecadal variability. For winter and spring, periodicities of about 50-60 years arise. The frequency of warm-dry and cold-wet modes appears correlated with the North Atlantic Oscillation (NAO), explaining mainly co-variability changes in spring. For winter and some regions in autumn, maximum and minimum P-T correlations appear in periods with enhanced meridional or easterly circulation (low or high pressure anomalies in the Mediterranean and Europe). In spring and summer, the Atlantic Multidecadal Oscillation shows some fingerprint on the frequency of warm/cold modes. For future scenarios, an intensification of the negative P-T relationship is generally found, as a result of an increased frequency of the warm-dry mode.

Metabolic adaptations of overwintering European common lizards (Lacerta vivipara).

PubMed

Voituron, Y; Hérold, J P; Grenot, C

2000-01-01

The European common lizard Lacerta vivipara, a reptile of cold-temperate climates, provides us an interesting model of low-temperature adaptation. Indeed its unique cold-hardiness strategy, which employs both freeze tolerance and freeze avoidance, may be seen as the primary reason for its large distribution, which extends from Spain to beyond the Arctic circle. To study the metabolism supporting this capacity, we used three techniques: two techniques of calorimetry (oxygen consumption and thermogenesis) and nuclear magnetic resonance spectroscopy. These techniques were used to examine the metabolic balance and the different molecular pathways used between three different periods through the year (September, January, and May). The results show a significant 20% augmentation of winter anaerobic metabolism compared to other periods of the year. This is mainly because of an activation of the lactic fermentation pathway leading to an increase of lactate concentration (>34% in winter). Furthermore, glucose, which increases some 245% in winter, is used as antifreeze and metabolic substrate. Furthermore, this study provides evidence that the physiological adaptations of the common lizard differ from those of other ectotherms such as Rana sylvatica. Concentrations of alanine and glycerol, commonly used as antifreeze by many overwintering ectotherms, do not increase during winter.

Impact of cold on the immune system of burying beetle, Nicrophorus vespilloides (Coleoptera: Silphidae).

PubMed

Urbański, Arkadiusz; Czarniewska, Elżbieta; Baraniak, Edward; Rosiński, Grzegorz

2017-06-01

Insect overwintering is one of the most astonishing phases of the insect life cycle. Despite vast amounts of knowledge available about the physiological mechanisms of this phenomenon, the impact of stress factors on insect immune system functioning during the winter is still unknown. The aim of this study is to analyze how low temperatures influence the immune system of the beetle Nicrophorus vespilloides. The results show that the beetle's immune system is differently modulated by cold induced in laboratory settings than that which occurs in natural conditions. Among beetles cultured in conditions similar to summer, low temperatures, did not influence the number of circulating haemocytes, phenoloxidase activity, haemocytes morphology, and percentage ratio of haemocyte types. In these beetles, differences were noted only in the ability of haemocytes to perform phagocytosis. Individuals acclimated in natural conditions in autumn had a higher level of humoral response and a different percentage ratio of haemocyte types. During the winter period, the number of haemocytes in the beetles decreased, but the percentage ratio of phagocytic haemocytes increased. Furthermore, we noted an increase of phenoloxidase activity. Our study also showed mitotic divisions of haemocytes in haemolymph collected from burying beetles after cold exposure and from burying beetles collected from natural conditions during autumn and winter. Differences in response to low temperatures in laboratory conditions and the natural environment suggest that the simultaneous presence of other stress factors during winter such as desiccation and starvation have a significant influence on the activity of burying beetle's immune system. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Organic and inorganic aerosol compositions in Ulaanbaatar, Mongolia, during the cold winter of 2007 to 2008: Dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls

NASA Astrophysics Data System (ADS)

Jung, Jinsang; Tsatsral, Batmunkh; Kim, Young J.; Kawamura, Kimitaka

2010-11-01

To investigate the distributions and sources of water-soluble organic acids in the Mongolian atmosphere, aerosol samples (PM2.5, n = 34) were collected at an urban site (47.92°N, 106.90°E, ˜1300 m above sea level) in Ulaanbaatar, the capital of Mongolia, during the cold winter. The samples were analyzed for water-soluble dicarboxylic acids (C2-C12) and related compounds (ketocarboxylic acids and α-dicarbonyls), as well as organic carbon (OC), elemental carbon, water-soluble OC, and inorganic ions. Distributions of dicarboxylic acids and related compounds were characterized by a predominance of terephthalic acid (tPh; 130 ± 51 ng m-3, 19% of total detected organic acids) followed by oxalic (107 ± 28 ng m-3, 15%), succinic (63 ± 20 ng m-3, 9%), glyoxylic (55 ± 18 ng m-3, 8%), and phthalic (54 ± 27 ng m-3, 8%) acids. Predominance of terephthalic acid, which has not been reported previously in atmospheric aerosols, was mainly due to uncontrolled burning of plastic bottles and bags in home stoves for heating and waste incineration during the cold winter. This study demonstrated that most of the air pollutants were directly emitted from local sources such as heat and power plants, home stoves, and automobiles. Development of an inversion layer (<700 m above ground level) over the basin of Ulaanbaatar accelerated the accumulation of pollutants, causing severe haze episodes during the winter season.

Experimental study on the monomer structure of solar semiconductor cold wall

NASA Astrophysics Data System (ADS)

Fu, Yuanyuan; Liu, Qiuxin; Chen, Tianshou

2018-06-01

In this paper, solar semiconductor cold wall structure was adopted in the net-zero energy buildings, NZEB for short. The heat transfer and refrigeration effect of the monomer structure of semiconductor cold wall were tested, we get that the monomer structure of semiconductor cold wall has certain cooling effect. However, the heat exchange effect is not good of the cold and hot aluminum plate only through natural convection and radiation heat transfer. It is necessary to further study the process of semiconductor refrigeration and heat transfer and the factors that affect the cooling effect. At the same time, it put forward a series of suggestions and improvement opinion for NZEB in hot summer and cold winter areas.

Cold-season temperature in the Swiss Alps from AD 1100-1500; trends, intra-annual variability and forcing factors

NASA Astrophysics Data System (ADS)

de Jong, Rixt; Kamenik, Christian; Grosjean, Martin

2010-05-01

To fully understand past climatic changes and their forcing factors, detailed reconstructions of past summer and winter temperatures are required. Winter temperature reconstructions are scarce, however, because most biological proxies are biased towards the growing season. This study presents a detailed reconstruction of winter temperatures based on Chrysophyte stomatocysts, silicious scales formed by so-called 'golden algae'. Previous studies (Kamenik and Schmidt, 2005; Pla and Catalan, 2005) have demonstrated the sensitivity of these algae to cold-season temperatures. Chrysophyte stomatocyst analysis was carried out on varved sediments from Lake Silvaplana (1791 m a.s.l.) at annual to near-annual resolution for two periods; AD 1100-1500 and AD 1870-2004. For both periods the reference date 'date of spring mixing' (Smix) was reconstructed using a transfer function developed for the Austrian Alps (Kamenik and Schmidt, 2005). In the Austrian Alps, Smix was primarily driven by air temperature in the cold season. The strength of stomatocysts as a proxy for winter temperature was tested by directly comparing reconstructed Smix with measured temperatures from nearby meteostation Sils Maria for the period AD 1870 - 2004. Correlation was highest (R = -0.6; p < 0.001) with mean October-April temperatures. The good agreement between reconstructed Smix and mean winter temperatures was interrupted only from AD 1925 - AD 1951, which was related to exceptionally high winter precipitation (thick snowpack) extending the ice-covered period. Strong lake eutrophication after AD 1950 only weakly affected the reconstruction of winter temperature. The winter temperature reconstruction (AD 1100-1500) shows strong interdecadal variability, superimposed on a cooling trend from around AD 1400 onwards. A direct comparison to summer temperature reconstructions based on biogenic silica and chironomid analysis from the same cores (Trachsel et al., in review; Larocque-Tobler et al., accepted manuscript) indicated strong fluctuations in intra-annual variability. A comparison to forcing factors shows that throughout the studied period, large tropical volcanic eruptions (Crowley, 2000) coincided with relatively warm winters in the study area. This is consistent with results from GCM experiments and observations of the limited number of eruptions during the much shorter instrumental period (Fischer et al., 2007). References: T. Crowley. Science 289, 270-277 (2000) E. Fischer et al. Geophys. Res. Lett. 34, L05707 (2007) C. Kamenik and R. Schmidt. Boreas 34, 477-489 (2005) I. Larocque-Tobler et al. Quat. Sci. Rev., accepted. S. Pla and J. Catalan. Clim. Dyn. 24, 263-278 (2005) M. Trachsel et al. Manuscript in review

Electricity unplugged

NASA Astrophysics Data System (ADS)

Karalis, Aristeidis

2009-02-01

The judge was driving back late one cold winter night. Entering the garage, the battery-charging indicator in his wirelessly powered electric car came on. "Home at last," crossed his mind. He swiped his personal smartcard on the front-door detector to be let in. He heard a "charging" beep from his mobile phone. The blinking cursor on the half-finished e-mail on the laptop had been waiting all day on the side table. He picked the computer up and walked towards his desk. "Good evening, your honour. Your wirelessly heated robe," said the butler-robot as it approached from the kitchen. Putting on the electric garment, he sat on the medical desk chair. His artificial heart was now beating faster.

Thermal biology, torpor use and activity patterns of a small diurnal marsupial from a tropical desert: sexual differences.

PubMed

Körtner, Gerhard; Rojas, A Daniella; Geiser, Fritz

2010-08-01

Many small desert dasyurids employ torpor almost daily during winter, because cold nights and low food availability impose high energetic costs. However, in Western Australia the arid zone extends into tropical, coastal regions, where winter temperature conditions are far less severe. We studied the thermal biology and activity patterns of free-ranging kaluta (approximately 27 g), a dasyurid restricted to these tropical spinifex deserts, during the Austral winter (June-July) and in addition quantified activity patterns in captivity. Unlike most dasyurids, wild and captive kalutas were almost exclusively diurnal and retreated into underground burrows during the night. Despite being active during the warmer part of the day, kalutas entered torpor daily. However, torpor patterns differed remarkably between males and females. While females spent most of the night torpid at body temperatures (T (b)) as low as 21 degrees C, close to soil temperature, males entered multiple short and shallow bouts (T (b) > 25 degrees C) during the night. Males also maintained higher T (b)s during the early morning when active, occupied larger home ranges and covered greater distances while foraging than females. Hence, males appear to expend more energy than the similar-sized females both while foraging and during the rest phase. We propose that physiological as well as behavioural preparations for the September mating season that culminate in a complete male die-off might already impose energetic costs on males during winter.

Metabolic Changes in Avena sativa Crowns Recovering from Freezing

PubMed Central

Henson, Cynthia A.; Duke, Stanley H.; Livingston, David P.

2014-01-01

Extensive research has been conducted on cold acclimation and freezing tolerance of fall-sown cereal plants due to their economic importance; however, little has been reported on the biochemical changes occurring over time after the freezing conditions are replaced by conditions favorable for recovery and growth such as would occur during spring. In this study, GC-MS was used to detect metabolic changes in the overwintering crown tissue of oat (Avena sativa L.) during a fourteen day time-course after freezing. Metabolomic analysis revealed increases in most amino acids, particularly proline, 5-oxoproline and arginine, which increased greatly in crowns that were frozen compared to controls and correlated very significantly with days after freezing. In contrast, sugar and sugar related metabolites were little changed by freezing, except sucrose and fructose which decreased dramatically. In frozen tissue all TCA cycle metabolites, especially citrate and malate, decreased in relation to unfrozen tissue. Alterations in some amino acid pools after freezing were similar to those observed in cold acclimation whereas most changes in sugar pools after freezing were not. These similarities and differences suggest that there are common as well as unique genetic mechanisms between these two environmental conditions that are crucial to the winter survival of plants. PMID:24675792

Cold Weather Entomology.

ERIC Educational Resources Information Center

McLure, John W.

1983-01-01

Suggests instructional strategies and student activities related to the study of insects during the winter. Includes possible collecting sites and classroom activities once the insects have been collected. (JN)

Study on indoor thermal environment in winter for rural residences in Yulin region

NASA Astrophysics Data System (ADS)

Yanjun, Li; Weixiao, Han

2018-02-01

Yulin region is located in the northern part of Shaanxi Province, China. The winter here is very cold and it has a long duration. In this paper, a rural residence which was located in Yulin region was taken as a study object. Indoor thermal environment of the rural residence were tested, including indoor air temperature and air relative humidity. Then, test data were analyzed. It was summarized that indoor thermal environment of test room can not fully meet human thermal comfort needs, and some tactics of regulation building thermal environment were proposed. This research contributes to improvement of indoor thermal environment for local rural residences and it provides reference for rural residences in other cold regions.

Should anthropogenic warming lead to more frequent cold air outbreaks over the northeastern U.S.?

NASA Astrophysics Data System (ADS)

Nicholas, R.

2014-12-01

For the northeastern United States, Winter 2013-14 was the coldest winter since the late 1970s and perhaps the coldest on record relative to prevailing climatic conditions. Frequent snowstorms and cold air outbreaks led to considerable press coverage and heated scholarly debate over the possible role of anthropogenic climate change in modulating wintertime variability in the northern hemisphere polar jet. While mechanisms have been proposed, to date, the observational record offers no definitive evidence for such a relationship, nor does it conclusively exclude one. To further explore this question, we employ a large, initial conditions ensemble of the Community Earth System Model forced with historical and RCP8.5 emissions. The ensemble effectively samples internal variability in the climate system and is used to assess the potential for forced changes in polar jet variability and the frequency of cold air outbreaks over the northeastern U.S. with projected increases in global mean temperature during the 21st century.

Evolutionary conservation of cold-induced antisense RNAs of FLOWERING LOCUS C in Arabidopsis thaliana perennial relatives.

PubMed

Castaings, Loren; Bergonzi, Sara; Albani, Maria C; Kemi, Ulla; Savolainen, Outi; Coupland, George

2014-07-17

Antisense RNA (asRNA) COOLAIR is expressed at A. thaliana FLOWERING LOCUS C (FLC) in response to winter temperatures. Its contribution to cold-induced silencing of FLC was proposed but its functional and evolutionary significance remain unclear. Here we identify a highly conserved block containing the COOLAIR first exon and core promoter at the 3' end of several FLC orthologues. Furthermore, asRNAs related to COOLAIR are expressed at FLC loci in the perennials A. alpina and A. lyrata, although some splicing variants differ from A. thaliana. Study of the A. alpina orthologue, PERPETUAL FLOWERING 1 (PEP1), demonstrates that AaCOOLAIR is induced each winter of the perennial life cycle. Introduction of PEP1 into A. thaliana reveals that AaCOOLAIR cis-elements confer cold-inducibility in this heterologous species while the difference between PEP1 and FLC mRNA patterns depends on both cis-elements and species-specific trans-acting factors. Thus, expression of COOLAIR is highly conserved, supporting its importance in FLC regulation.

Satellite Sees Winter Storm March Over Mid-Atlantic

NASA Image and Video Library

2014-03-03

On March 3, a major winter storm brought snow to the mid-Atlantic, freezing rain to the Carolinas and rain and some freezing rain to the Gulf Coast states. NOAA's GOES-East satellite captured an image of the clouds associated with the winter storm on March 3 at 12:45 p.m. EST (1745 UTC)/ as it continued on its march over the mid-Atlantic. Bands of snow and sometimes heavy snow affected the Washington, D.C., region, Delaware and central Virginia, stretching west into West Virginia and eastern Kentucky. Snow also stretched back into the Ohio and Tennessee valleys while rain and freezing rain affected the Carolinas, and while the Gulf Coast states received rain. National Weather Service Winter Storm Warnings remained in effect until 6 p.m. EST on March 3 for Washington, D.C., and Baltimore, Md. In Richmond and Norfolk, Va., the Winter Storm warnings were in effect for six additional hours ending at midnight. On March 3, NOAA's National Weather Prediction Center in College Park, Md., noted the late-season winter storm will continue to shift eastward through the Tennessee Valley and the mid-Atlantic today, making for hazardous travel conditions. NOAA noted that unseasonably cold temperatures more typical of January will prevail east of the Rocky Mountains for the next few days keeping winter around for a while longer. The clouds are associated with a cold front that stretched from eastern Maine through Maryland and west into the Tennessee Valley. At NASA/NOAA's GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md., the cloud data from NOAA's GOES-East satellite were overlaid on a true-color image of land and ocean created by data from the Moderate Resolution Imaging Spectroradiometer, or MODIS, instrument that flies aboard NASA's Aqua and Terra satellites. Together, those data created the entire picture of the position of this major winter storm. GOES satellites provide the kind of continuous monitoring necessary for intensive data analysis. Geostationary describes an orbit in which a satellite is always in the same position with respect to the rotating Earth. This allows GOES to hover continuously over one position on Earth's surface, appearing stationary. As a result, GOES provide a constant vigil for the atmospheric "triggers" for severe weather conditions such as tornadoes, flash floods, hail storms and hurricanes. For updated information about the storm system, visit NOAA's NWS website: www.weather.gov For more information about GOES satellites, visit: www.goes.noaa.gov/ or goes.gsfc.nasa.gov/ Rob Gutro NASA's Goddard Space Flight Center, Greenbelt, Md. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

[Low-temperature response and cold tolerance at spike differentiation stage of winter wheat varieties sowed in spring].

PubMed

Xu, Lan; Gao, Zhi-fiang; An, Wei; Yuan, Ya-qi; Li, Yan-liang

2015-06-01

A total of 10 winter wheat varieties were imported from the middle and lower reaches of the Yangtze River region in China. Those varieties were sowed in spring in Xinding basin area of Shanxi Province, and the field trials were performed for two years (2013-2014). The traits and physiological characteristics under low temperature stress including grain yield, total content of chlorophyll, osmotic adjustment, membrane system, ion leakage rate, contents of soluble sugar and soluble protein were investigated, and the cold tolerance levels of the wheat varieties were assessed. The results showed that low temperature stress led to increases in wheat leaf ion leakage rate, soluble sugar and protein contents, but obvious reduction of chlorophyll content. According to principal component analysis and cold tolerance (D value) , Yumai 10, Yangmai 20, and Yunmai 42 were classed as cold sensitive wheat varieties. Yangmai 13, Yumai 12, and Ningmai 13 were classed as stronger cold-resistant wheat genotypes, and showed stability through two-year field trials, with the D values being 0.665-0.659, 0.493-0.495, and 0.471-0.583, respectively, while the D values for the controls Ning 2038 and Xinchun 30 were 0.368-0.397, and 0.328-0.330, respectively. The grain yields of the cold resistant wheat varieties were significantly higher than that of the other varieties tested. Therefore, Yangmai 13, Yumai 12 and Ningmai 13 could be imported and used as the cold tolerant wheat varieties for North Plain of China.

Seasonal- and temperature-dependent variation in CNS ascorbate and glutathione levels in anoxia-tolerant turtles.

PubMed

Pérez-Pinzón, M A; Rice, M E

1995-12-24

We determined the ascorbic acid (ascorbate) and glutathione (GSH) contents of eight regions of the CNS from anoxia-tolerant turtles collected in summer and in winter. Ascorbate was of special interest because it is found in exceptionally high levels in the turtle CNS. The temperature-dependence of CNS ascorbate content was established by comparing levels in animals collected from two geographic zones with different average winter temperatures and in animals re-acclimated to different temperatures in the laboratory. The analytical method was liquid chromatography with electrochemical detection. Turtle ascorbate levels were 30-40% lower in animals acclimatized to winter (2 degrees C) than to summer (23 degrees C) in all regions of the CNS. Similarly, GSH levels were 20-30% lower in winter than in summer. Winter ascorbate levels were higher in turtles from Louisiana (19 degrees C) than in turtles acclimatized to winter in Wisconsin (2 degrees C). Summer and winter levels of ascorbate could be reversed by re-acclimating animals to cold (1 degree C) or warm (23 degrees C) temperatures for at least one week. CNS water content did not differ between cold- and warm-acclimated turtles. Taken together, the data indicated that ascorbate and GSH undergo significant seasonal variation and that the catalyst for change is environmental temperature. Steady-state ascorbate content showed a linear dependence on temperature, with a slope of 1.5% per degree C that was independent of CNS region. Lower levels of cerebral antioxidants in turtles exposed to colder temperatures were consistent with the decreased rate of cerebral metabolism that accompanies winter hibernation. Cerebral ascorbate and GSH levels in the turtle remained similar to or higher than those in mammals, even during winter, however. These findings support the notion that unique mechanisms of antioxidant regulation in the turtle contribute to their tolerance of the hypoxia-reoxygenation that characterizes diving behavior.

Impacts of extreme climatic events on the energetics of long-lived vertebrates: the case of the greater flamingo facing cold spells in the Camargue.

PubMed

Deville, Anne-Sophie; Labaude, Sophie; Robin, Jean-Patrice; Béchet, Arnaud; Gauthier-Clerc, Michel; Porter, Warren; Fitzpatrick, Megan; Mathewson, Paul; Grémillet, David

2014-10-15

Most studies analyzing the effects of global warming on wild populations focus on gradual temperature changes, yet it is also important to understand the impact of extreme climatic events. Here we studied the effect of two cold spells (January 1985 and February 2012) on the energetics of greater flamingos (Phoenicopterus roseus) in the Camargue (southern France). To understand the cause of observed flamingo mass mortalities, we first assessed the energy stores of flamingos found dead in February 2012, and compared them with those found in other bird species exposed to cold spells and/or fasting. Second, we evaluated the monthly energy requirements of flamingos across 1980-2012 using the mechanistic model Niche Mapper. Our results show that the body lipids of flamingos found dead in 2012 corresponded to 2.6±0.3% of total body mass, which is close to results found in woodcocks (Scolopax rusticola) that died from starvation during a cold spell (1.7±0.1%), and much lower than in woodcocks which were fed throughout this same cold spell (13.0±2%). Further, Niche Mapper predicted that flamingo energy requirements were highest (+6-7%) during the 1985 and 2012 cold spells compared with 'normal' winters. This increase was primarily driven by cold air temperatures. Overall, our findings strongly suggest that flamingos starved to death during both cold spells. This study demonstrates the relevance of using mechanistic energetics modelling and body condition analyses to understand and predict the impact of extreme climatic events on animal energy balance and winter survival probabilities. © 2014. Published by The Company of Biologists Ltd.

Cold tolerance and photosystem function in a montane red spruce population: physiological relationships with foliar carbohydrates

Treesearch

P.G. Schaberg; G.R. Strimbeck; G.J. Hawley; D.H. DeHayes; J.B. Shane; P.F. Murakami; T.D. Perkins; J.R. Donnelly; B.L. Wong

2000-01-01

Red spruce (Picea rubens Sarg.) growing in northern montane forests of eastern North America appears to be distinctive with respect to at least two aspects of winter physiology. First, red spruce attains only a modest level of midwinter cold tolerance compared to other north temperate conifers and appears barely capable of avoiding freezing injury at...

Osmotic and elastic adjustments in cold desert shrubs differing in rooting depth: coping with drought and subzero temperatures

Treesearch

Fabian G. Scholz; Sandra J. Bucci; Nadia Arias; Frederick C. Meinzer; Guillermo Goldstein

2012-01-01

Physiological adjustments to enhance tolerance or avoidance of summer drought and winter freezing were studied in shallow- to deep-rooted Patagonian cold desert shrubs. We measured leaf water potential, osmotic potential, tissue elasticity, stem hydraulic characteristics, and stomatal conductance across species throughout the year, and assessed tissue damage by subzero...

Impact of the pathogen Pyrenophora semeniperda on Bromus tectorum seedbank dynamics in North American cold deserts

Treesearch

S. E. Meyer; D. Quinney; D. L. Nelson; J. Weaver

2007-01-01

Bromus tectorum is a dominant winter annual weed in cold deserts of western North America. We followed patterns of seed carry-over and abundance of the pathogen Pyrenophora semeniperda over 5 years at B. tectorum-dominated shadscale (Atriplex confertifolia) and sagebrush (Artemisia tridentata) sites in southern Idaho. We hypothesised that more seeds could potentially...

Variation in waterlogging-triggered stomatal behavior contributes to changes in the cold acclimation process in prehardened Lolium perenne and Festuca pratensis.

PubMed

Jurczyk, Barbara; Pociecha, Ewa; Janowiak, Franciszek; Kabała, Dawid; Rapacz, Marcin

2016-12-01

According to predicted changes in climate, waterlogging events may occur more frequently in the future during autumn and winter at high latitudes of the Northern Hemisphere. If excess soil water coincides with the process of cold acclimation for plants, winter survival may potentially be affected. The effects of waterlogging during cold acclimation on stomatal aperture, relative water content, photochemical activity of photosystem II, freezing tolerance and plant regrowth after freezing were compared for two prehardened overwintering forage grasses, Lolium perenne and Festuca pratensis. The experiment was performed to test the hypothesis that changes in photochemical activity initiated by waterlogging-triggered modifications in the stomatal aperture contribute to changes in freezing tolerance. Principal component analysis showed that waterlogging activated different adaptive strategies in the two species studied. The increased freezing tolerance of F. pratensis was associated with increased photochemical activity connected with stomatal opening, whereas freezing tolerance of L. perenne was associated with a decrease in stomatal aperture. In conclusion, waterlogging-triggered stomatal behavior contributed to the efficiency of the cold acclimation process in L. perenne and F. pratensis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Does the recent warming hiatus exist over northern Asia for winter wind chill temperature?

NASA Astrophysics Data System (ADS)

Ma, Ying

2017-04-01

Wind chill temperature (WCT) describes the joint effect of wind velocity and air temperature on exposed body skin and could support policy makers in designing plans to reduce the risks of notably cold and windy weather. This study examined winter WCT over northern Asia during 1973-2013 by analyzing in situ station data. The winter WCT warming rate over the Tibetan Plateau slowed during 1999-2013 (-0.04 °C/decade) compared with that during 1973-1998 (0.67 °C/decade). The winter WCT warming hiatus has also been observed in the remainder of Northern Asia with trends of 1.11 °C/decade during 1973-1998 but -1.02 °C/decade during 1999-2013, except for the Far East of Russia (FE), where the winter WCT has continued to heat up during both the earlier period of 1973-1998 (0.54 °C/decade) and the recent period of 1999-2013 (0.75 °C/decade). The results indicate that the influence of temperature on winter WCT is greater than that of wind speed over northern Asia. Atmospheric circulation changes associated with air temperature and wind speed were analyzed to identify the causes for the warming hiatus of winter WCT over northern Asia. The distributions of sea level pressure and 500 hPa height anomalies during 1999-2013 transported cold air from the high latitudes to middle latitudes, resulting in low air temperature over Northern Asia except for the Far East of Russia. Over the Tibetan Plateau, the increase in wind speed offset the increase in air temperature during 1999-2013. For the Far East, the southerly wind from the Western Pacific drove the temperature up during the 1999-2013 period via warm advection.

The big chill: quantifying the effect of the 2014 North American cold wave on hemlock woolly adelgid populations in the central Appalachian Mountains

Treesearch

Patrick C. Tobin; Richard M. Turcotte; Laura M. Blackburn; John A. Juracko; Brian T. Simpson

2017-01-01

The ability to survive winter temperatures is a key determinant of insect distributional ranges and population dynamics in temperate ecosystems. Although many insects overwinter in a state of diapause, the hemlock woolly adelgid [Adelges tsugae (Annand)] is an exception and instead develops during winter. We studied a low density population of

Ice fishing by wintering Bald Eagles in Arizona

Treesearch

Teryl G. Grubb; Roy G. Lopez

1997-01-01

Northern Arizona winters vary within and between years with occasional heavy snows (up to 0.6 m) and extreme cold (overnight lows -18 to -29°C) interspersed with dry periods, mild temperatures (daytime highs reaching 10°C), and general loss of snow cover at all but highest elevations. Lakes in the area may freeze and thaw partially or totally several times during a...

Comprehensive transcriptome analyses reveal differential gene expression profiles of Camellia sinensis axillary buds at para-, endo-, ecodormancy, and bud flush stages

USDA-ARS?s Scientific Manuscript database

Winter dormancy is an important biological feature for tea plant to survive cold winters, and it also affects the economic output of tea plant, one of the few woody plants in the world whose leaves are harvested and one of the few non-conifer evergreen species with characterized dormancies. To disco...

NCAR CCM2 simulation of the modern Antarctic climate

NASA Technical Reports Server (NTRS)

Tzeng, Ren-Yow; Bromwich, David H.; Parish, Thomas R.; Chen, Biao

1994-01-01

The National Center for Atmospheric Research (NCAR) community climate model version 2 (CCM2) simulation of the circumpolar trough, surface air temperature, the polar vortex, cloudiness, winds, and atmospheric moisture and energy budgets are examined to validate the model's representation of the present-day Antarctic climate. The results show that the CCM2 can well simulate many important climate features over Antarctica, such as the location and intensity of the circumpolar trough, the coreless winter over the plateau, the intensity and horizontal distribution of the surface inversion, the speed and streamline pattern of the katabatic winds, the double jet stream feature over the southern Indian and Pacific oceans, and the arid climate over the continent. However, there are also some serious errors in the model. Some are due to old problems but some are caused by the new parameterizations in the model. The model errors over high southern latitudes can be summarized as follows: The circumpolar trough, the polar vertex, and the westerlies in midlatitudes are too strong; the semiannual cycle of the circumpolar trough is distorted compared to the observations; the low centers of the circumpolar trough and the troughs in the middle and upper troposphere are shifted eastward by 15 deg - 40 deg longitude; the surface temperatures are too cold over the plateau in summer and over the coastline in winter; the polar tropopause continues to have a cold bias; and the cloudiness is too high over the continent. These biases are induced by two major factors: (1) the cloud optical properties in tropical and middle latitudes, which cause the eastward shift of troughs and surface low centers and the error in the semiannual cycle, and (2) the cold bias of the surface air temperature, which is attributed to the oversimulation of cloudiness over the continent, especially during summer, and the uniform 2-m-thick sea ice. The constant thickness of sea ice suppresses the energy flux from the ocean to the atmosphere and hence reduces the air temperature near the coast during winter. Finally, although the simulated Antarctic climate still suffers these biases, the overall performance of the CCM2 is much better than that of the CCM1-T42. Therefore the CCM2 is good enough to be used for climate change studies, especially over Antarctica.

Dust transport over Iraq and northwest Iran associated with winter Shamal: A case study

NASA Astrophysics Data System (ADS)

Abdi Vishkaee, Farhad; Flamant, Cyrille; Cuesta, Juan; Oolman, Larry; Flamant, Pierre; Khalesifard, Hamid R.

2012-02-01

Dynamical processes leading to dust emission over Syria and Iraq, in response to a strong winter Shamal event as well as the subsequent transport of dust over Iraq and northwest Iran, are analyzed on the basis of a case study (22-23 February 2010) using a suite of ground-based and spaceborne remote sensing platforms together with modeling tools. Surface measurements on 22 February show a sharp reduction in horizontal visibility over Iraq occurring shortly after the passage of a cold front (behind which the northwesterly Shamal winds were blowing) and that visibilities could be as low as 1 km on average for 1-2 days in the wake of the front. The impact of the southwesterly Kaus winds blowing ahead (east) of the Shamal winds on dust emission over Iraq is also highlighted. Unlike what is observed over Iraq, low near-surface horizontal visibilities (<1 km) over northwest Iran are observed well after the passage of the cold front on 23 February, generally in the hours following sunrise. Ground-based lidar measurements acquired in Zanjan show that, in the wake of the front, dust from Syria/Iraq was transported in an elevated 1 to 1.5 km thick plume separated from the surface during the night/morning of 23 February. After sunrise, strong turbulence in the developing convective boundary layer led to mixing of the dust into the boundary layer and in turn to a sharp reduction of the horizontal visibility in Zanjan. The timing of the reduction of surface horizontal visibility in other stations over northwest Iran (Tabriz, Qom, and Tehran) is consistent with the downward mixing of dust in the planetary boundary layer just after sunset, as evidenced in Zanjan. This study sheds new light on the processes responsible for dust emission and transport over Iraq and northwest Iran in connection with winter Shamal events. Enhanced knowledge of these processes is key for improving dust forecasts in this region.

Observation of dust emission and transport over Iraq and northwest Iran associated with winter Shamal

NASA Astrophysics Data System (ADS)

Flamant, C.; Abdi Vishkaee, F.; Cuesta, J.; Khalesifard, H.; Oolman, L.; Flamant, P.

2012-04-01

Dynamical processes leading to dust emission over Syria and Iraq, in response to a strong winter Shamal event as well as the subsequent transport of dust over Iraq and northwest Iran, are analyzed on the basis of a case study (22-23 February 2010) using a suite of ground-based and space-borne remote sensing platforms together with modeling tools. Surface measurements on 22 February show a sharp reduction in horizontal visibility over Iraq occurring shortly after the passage of a cold front (behind which the northwesterly Shamal winds were blowing) and that visibilities could be as low as 1 km on average for one to two days in the wake of the front. The impact of the southwesterly Kaus winds blowing ahead (east) of the Shamal winds on dust emission over Iraq is also highlighted. Unlike what is observed over Iraq, low near-surface horizontal visibilities (less than 1 km) over northwest Iran are observed well after the passage of the cold front on 23 February, generally in the hours following sunrise. Ground-based lidar measurements acquired in Zanjan show that, in the wake of the front, dust from Syria/Iraq was transported in an elevated 1 to 1.5 km thick plume separated from the surface during the night/morning of February. After sunrise, strong turbulence in the developing convective boundary layer led to mixing of the dust into the boundary layer and in turn to a sharp reduction of the horizontal visibility in Zanjan. The timing of the reduction of surface horizontal visibility in other stations over northwest Iran (Tabriz, Qom and Tehran) is consistent with the downward mixing of dust in the PBL just after sunset, as evidenced in Zanjan. This study shades new light on the processes responsible for dust emission and transport over Iraq and northwest Iran in connection with winter Shamal events. Enhanced knowledge of these processes is key for improving dust forecasts in this region.

Snow-atmosphere coupling and its impact on temperature variability and extremes over North America

NASA Astrophysics Data System (ADS)

Diro, G. T.; Sushama, L.; Huziy, O.

2018-04-01

The impact of snow-atmosphere coupling on climate variability and extremes over North America is investigated using modeling experiments with the fifth generation Canadian Regional Climate Model (CRCM5). To this end, two CRCM5 simulations driven by ERA-Interim reanalysis for the 1981-2010 period are performed, where snow cover and depth are prescribed (uncoupled) in one simulation while they evolve interactively (coupled) during model integration in the second one. Results indicate systematic influence of snow cover and snow depth variability on the inter-annual variability of soil and air temperatures during winter and spring seasons. Inter-annual variability of air temperature is larger in the coupled simulation, with snow cover and depth variability accounting for 40-60% of winter temperature variability over the Mid-west, Northern Great Plains and over the Canadian Prairies. The contribution of snow variability reaches even more than 70% during spring and the regions of high snow-temperature coupling extend north of the boreal forests. The dominant process contributing to the snow-atmosphere coupling is the albedo effect in winter, while the hydrological effect controls the coupling in spring. Snow cover/depth variability at different locations is also found to affect extremes. For instance, variability of cold-spell characteristics is sensitive to snow cover/depth variation over the Mid-west and Northern Great Plains, whereas, warm-spell variability is sensitive to snow variation primarily in regions with climatologically extensive snow cover such as northeast Canada and the Rockies. Furthermore, snow-atmosphere interactions appear to have contributed to enhancing the number of cold spell days during the 2002 spring, which is the coldest recorded during the study period, by over 50%, over western North America. Additional results also provide useful information on the importance of the interactions of snow with large-scale mode of variability in modulating temperature extreme characteristics.

Increasing species richness of the macrozoobenthic fauna on tidal flats of the Wadden Sea by local range expansion and invasion of exotic species

NASA Astrophysics Data System (ADS)

Beukema, J. J.; Dekker, R.

2011-06-01

A 40-y series of consistently collected samples (15 fixed sampling sites, constant sampled area of 15 × 0.95 m2, annual sampling only in late-winter/early-spring seasons, and consistent sieving and sorting procedures; restriction to 50 easily recognizable species) of macrozoobenthos on Balgzand, a tidal flat area in the westernmost part of the Wadden Sea (The Netherlands), revealed significantly increasing trends of species richness. Total numbers of species annually encountered increased from ~28 to ~38. Mean species density (number of species found per sampling site) increased from ~13 to ~18 per 0.95 m2. During the 40 years of the 1970-2009 period of observation, 4 exotic species invaded the area: (in order of first appearance) Ensis directus, Marenzelleria viridis, Crassostrea gigas, and Hemigrapsus takanoi. Another 5 species recently moved to Balgzand from nearby (subtidal) locations. Together, these 9 new species on the tidal flats explained by far most of the increase in total species numbers, but accounted for only one-third of the observed increase in species density (as a consequence of the restricted distribution of most of them). Species density increased particularly by a substantial number of species that showed increasing trends in the numbers of tidal flat sites they occupied. Most of these wider-spreading species were found to suffer from cold winters. During the 40-y period of observation, winter temperatures rose by about 2°C and cold winters became less frequent. The mean number of cold-sensitive species found per site significantly increased by almost 2 per 0.95 m2. Among the other species (not sensitive to low winter temperatures), 6 showed a rising and 2 a declining trend in number of occupied sites, resulting in a net long-term increase in species density amounting to another gain of 1.6 per 0.95 m2. Half of the 50 studied species did not show such long-term trend, nor were invaders. Thus, each of 3 groups (local or alien invaders/winter-sensitive species/other increasing species) contributed to a roughly similar extent to the overall increase in species density.

Light-quality and temperature-dependent CBF14 gene expression modulates freezing tolerance in cereals.

PubMed

Novák, Aliz; Boldizsár, Ákos; Ádám, Éva; Kozma-Bognár, László; Majláth, Imre; Båga, Monica; Tóth, Balázs; Chibbar, Ravindra; Galiba, Gábor

2016-03-01

C-repeat binding factor 14 (CBF14) is a plant transcription factor that regulates a set of cold-induced genes, contributing to enhanced frost tolerance during cold acclimation. Many CBF genes are induced by cool temperatures and regulated by day length and light quality, which affect the amount of accumulated freezing tolerance. Here we show that a low red to far-red ratio in white light enhances CBF14 expression and increases frost tolerance at 15°C in winter Triticum aesitivum and Hordeum vulgare genotypes, but not in T. monococcum (einkorn), which has a relatively low freezing tolerance. Low red to far-red ratio enhances the expression of PHYA in all three species, but induces PHYB expression only in einkorn. Based on our results, a model is proposed to illustrate the supposed positive effect of phytochrome A and the negative influence of phytochrome B on the enhancement of freezing tolerance in cereals in response to spectral changes of incident light. CBF-regulon, barley, cereals, cold acclimation, freezing tolerance, light regulation, low red/far-red ratio, phytochrome, wheat. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Latitudinal variation in diapause duration and post-winter development in two pierid butterflies in relation to phenological specialization.

PubMed

Posledovich, Diana; Toftegaard, Tenna; Wiklund, Christer; Ehrlén, Johan; Gotthard, Karl

2015-01-01

Diapause plays a central role in insect life cycles by allowing survival during adverse seasonal conditions as well as synchronizing life cycles with the period of mate and food availability. Seasonal timing is expected to be particularly important for species that are dependent on resources available during a short time window-so-called phenological specialists-and latitudinal clines in seasonality are expected to favor local adaptation in phenological timing. However, to what degree latitudinal variation in diapause dynamics and post-winter development due to such local adaptation is influenced by the degree of phenological specialization is not well known. We experimentally studied two pierid butterfly species and found that the phenological specialist Anthocharis cardamines had shorter diapause duration than the phenological generalist Pieris napi along a latitudinal gradient in Sweden. Moreover, diapause duration increased with latitude in P. napi but not in A. cardamines. Sensitivity of the two species to winter thermal conditions also differed; additional cold temperature during the winter period shortened diapause duration for P. napi pupae but not for A. cardamines pupae. In both species, post-winter pupal development was faster after longer periods of cold conditions, and more southern populations developed faster than northern populations. Post-winter development was also invariably faster at higher temperatures in both species. We argue that the observed differences in diapause dynamics between the two species might be explained by the difference in phenological specialization that influences the costs of breaking diapause too early in the season.

Habitat quality affects stress responses and survival in a bird wintering under extremely low ambient temperatures

NASA Astrophysics Data System (ADS)

Cīrule, Dina; Krama, Tatjana; Krams, Ronalds; Elferts, Didzis; Kaasik, Ants; Rantala, Markus J.; Mierauskas, Pranas; Luoto, Severi; Krams, Indrikis A.

2017-12-01

Animals normally respond to stressful environmental stimuli by releasing glucocorticoid hormones. We investigated whether baseline corticosterone (CORT), handling-induced corticosterone concentration(s), and body condition indices of members of willow tit ( Poecile montanus) groups differed while wintering in old growth forests and managed young forests in mild weather conditions and during cold spells. Willow tits spend the winter season in non-kin groups in which dominant individuals typically claim their priority to access resources, while subordinate individuals may experience greater levels of stress and higher mortality, especially during cold spells. We captured birds to measure baseline CORT and levels of handling-induced CORT secretion after 20 min of capture. Willow tits in the young forests had higher baseline CORT and a smaller increase in CORT in response to capture than individuals in the old forests. Baseline CORT was higher in females and juvenile birds compared to adult males, whereas handling-induced CORT secretion did not differ between birds of different ages. During cold spells, baseline CORT of willow tits increased and handling-induced CORT secretion decreased, especially in birds in young forests. Willow tits' survival was higher in the old forests, with dominant individuals surviving better than subordinates. Our results show that changes in CORT secretion reflect responses to habitat quality and climate harshness, indicating young managed coniferous forests as a suboptimal habitat for the willow tit.

Winter circulation weather types and hospital admissions for respiratory diseases in Galicia, Spain

NASA Astrophysics Data System (ADS)

Royé, D.; Taboada, J. J.; Martí, A.; Lorenzo, M. N.

2016-04-01

The link between various pathologies and atmospheric conditions has been a constant topic of study over recent decades in many places across the world; knowing more about it enables us to pre-empt the worsening of certain diseases, thereby optimizing medical resources. This study looked specifically at the connections in winter between respiratory diseases and types of atmospheric weather conditions (Circulation Weather Types, CWT) in Galicia, a region in the north-western corner of the Iberian Peninsula. To do this, the study used hospital admission data associated with these pathologies as well as an automatic classification of weather types. The main result obtained was that weather types giving rise to an increase in admissions due to these diseases are those associated with cold, dry weather, such as those in the east and south-east, or anticyclonic types. A second peak was associated with humid, hotter weather, generally linked to south-west weather types. In the future, this result may help to forecast the increase in respiratory pathologies in the region some days in advance.

Winter circulation weather types and hospital admissions for respiratory diseases in Galicia, Spain.

PubMed

Royé, D; Taboada, J J; Martí, A; Lorenzo, M N

2016-04-01

The link between various pathologies and atmospheric conditions has been a constant topic of study over recent decades in many places across the world; knowing more about it enables us to pre-empt the worsening of certain diseases, thereby optimizing medical resources. This study looked specifically at the connections in winter between respiratory diseases and types of atmospheric weather conditions (Circulation Weather Types, CWT) in Galicia, a region in the north-western corner of the Iberian Peninsula. To do this, the study used hospital admission data associated with these pathologies as well as an automatic classification of weather types. The main result obtained was that weather types giving rise to an increase in admissions due to these diseases are those associated with cold, dry weather, such as those in the east and south-east, or anticyclonic types. A second peak was associated with humid, hotter weather, generally linked to south-west weather types. In the future, this result may help to forecast the increase in respiratory pathologies in the region some days in advance.

Early prediction of extreme stratospheric polar vortex states based on causal precursors

NASA Astrophysics Data System (ADS)

Kretschmer, Marlene; Runge, Jakob; Coumou, Dim

2017-08-01

Variability in the stratospheric polar vortex (SPV) can influence the tropospheric circulation and thereby winter weather. Early predictions of extreme SPV states are thus important to improve forecasts of winter weather including cold spells. However, dynamical models are usually restricted in lead time because they poorly capture low-frequency processes. Empirical models often suffer from overfitting problems as the relevant physical processes and time lags are often not well understood. Here we introduce a novel empirical prediction method by uniting a response-guided community detection scheme with a causal discovery algorithm. This way, we objectively identify causal precursors of the SPV at subseasonal lead times and find them to be in good agreement with known physical drivers. A linear regression prediction model based on the causal precursors can explain most SPV variability (r2 = 0.58), and our scheme correctly predicts 58% (46%) of extremely weak SPV states for lead times of 1-15 (16-30) days with false-alarm rates of only approximately 5%. Our method can be applied to any variable relevant for (sub)seasonal weather forecasts and could thus help improving long-lead predictions.

Seasonal variation of carcass decomposition and gravesoil chemistry in a cold (Dfa) climate.

PubMed

Meyer, Jessica; Anderson, Brianna; Carter, David O

2013-09-01

It is well known that temperature significantly affects corpse decomposition. Yet relatively few taphonomy studies investigate the effects of seasonality on decomposition. Here, we propose the use of the Köppen-Geiger climate classification system and describe the decomposition of swine (Sus scrofa domesticus) carcasses during the summer and winter near Lincoln, Nebraska, USA. Decomposition was scored, and gravesoil chemistry (total carbon, total nitrogen, ninhydrin-reactive nitrogen, ammonium, nitrate, and soil pH) was assessed. Gross carcass decomposition in summer was three to seven times greater than in winter. Initial significant changes in gravesoil chemistry occurred following approximately 320 accumulated degree days, regardless of season. Furthermore, significant (p < 0.05) correlations were observed between ammonium and pH (positive correlation) and between nitrate and pH (negative correlation). We hope that future decomposition studies employ the Köppen-Geiger climate classification system to understand the seasonality of corpse decomposition, to validate taphonomic methods, and to facilitate cross-climate comparisons of carcass decomposition. © 2013 American Academy of Forensic Sciences.

Autumn Frost, North Polar Sand Dunes

NASA Technical Reports Server (NTRS)

1999-01-01

Autumn in the martian northern hemisphere began around August 1, 1999. Almost as soon as northern fall began, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) started documenting the arrival of autumn frost--a precursor to the cold winter that will arrive in late December 1999. The first features to become covered by frost were the sand dunes that surround the north polar ice cap. The dunes seen here would normally appear very dark--almost black--except when covered by frost. Why the dunes begin to frost sooner than the surrounding surfaces is a mystery: perhaps the dunes contain water vapor that emerges from the sand during the day and condenses again at night. This picture shows dunes near 74.7oN, 61.4oW at a resolution of about 7.3 meters (24 feet) per pixel. The area covered is about 3 km (1.9 mi) across and is illuminated from the upper right. The picture appears to be somewhat fuzzy and grainy because the dunes here are seen through the thin haze of the gathering north polar winter hood (i.e., clouds).

Linked Extreme Weather Events during Winter 2009-2010 and 2010-2011 in the Context of Northern Hemisphere Circulation Anomalies

NASA Astrophysics Data System (ADS)

Bosart, L. F.; Archambault, H. M.; Cordeira, J. M.

2011-12-01

Lance F. Bosart, Heather M. Archambault, and Jason M. Cordeira Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, New York The Northern Hemisphere (NH) planetary-scale circulation during winter 2009-2010 was characterized by an unusual combination of persistent high-latitude blocking and southward-displaced storm tracks, manifest by a strongly negative Arctic Oscillation (AO), in conjunction with a moderate El Nino event. The high-latitude blocking activity and southward-displaced storm tracks supported episodic cold-air outbreaks and enhanced storminess over parts of midlatitude eastern Asia, eastern North America, and western Europe as well as anomalous warmth over northeastern Canada and Greenland that delayed sea ice formation and ice thickening in these areas during winter 2009-2010. Although somewhat less extreme than winter 2009-2010, the first half of winter 2010-2011 was also characterized by high-latitude blocking and southward-displaced storm tracks (manifest by negative values of the AO) while the Pacific-North American (PNA), initially negative, became neutral in late December and most of January. Winter 2010-2011 was characterized by moderate La Nina conditions in contrast to moderate El Nino conditions that prevailed during winter 2009-2010. Despite the reversal of the ENSO phase from winter 2009-2010 to winter 2010-2011, high-latitude blocking activity and the associated southward-displaced storm tracks again allowed for episodic cold-air outbreaks and enhanced storminess over parts of midlatitude eastern Asia, central and eastern North America, and western Europe with delayed sea ice formation and thickening over the Davis Strait and adjacent regions during the first half of winter 2010-2011. Beginning in late January and continuing through early February 2011 the phase of the AO and the PNA reversed with the AO and PNA becoming positive and negative, respectively. This linked AO/PNA phase transition was associated with an extreme weather event that brought severe and record-setting cold to parts of the U.S. and Mexico, a powerful snow and ice storm in the Central U.S., and a subsequent and spectacular warm-up east of the Rockies. The purpose of this presentation will be to present an overview of the structure and evolution of the large-scale NH circulation anomalies during the 2009-2010 and 2010-2011 winters. Emphasis will be placed on showing how individual synoptic-scale weather events (e.g., recurving and transitioning western Pacific tropical cyclones, diabatically driven upper-level outflow from organized deep convection associated with the Madden-Julian Oscillation, and western North Atlantic storminess) contributed to the formation of significant and persistent large-scale circulation anomalies and how these large-scale circulation anomalies in turn impacted the storm tracks, regional temperature and precipitation anomalies, and the associated extreme weather.

Xerosis

MedlinePlus

... Causes Dry skin can be caused by: The climate, such as cold, dry winter air or hot, ... Medical Dermatology, Associate Professor of Dermatology, Mayo Medical School, Scottsdale, AZ. Also reviewed by David Zieve, MD, ...

Impact of northern Eurasian snow cover in autumn on the warm Arctic-cold Eurasia pattern during the following January and its linkage to stationary planetary waves

NASA Astrophysics Data System (ADS)

Xu, Xinping; He, Shengping; Li, Fei; Wang, Huijun

2018-03-01

The connection between Eurasian snow cover (SC) in autumn and Eurasian winter mean surface air temperature (SAT) has been identified by many studies. However, some recent observations indicate that early and late winter climate sometimes shows an out-of-phase relationship, suggesting that the winter mean situation might obscure the important relationships that are relevant for scientific research and applications. This study investigates the relationship between October northern Eurasian SC (NESC; 58°-68°N, 30°-90°E) and Eurasian SAT during the winter months and finds a significant relationship only exists in January. Generally, following reduced October NESC, the East Asian trough and Ural high are intensified in January, and anomalous northeasterly winds prevail in mid-latitudes, causing cold anomalies over Eurasia. Meanwhile, anomalous southwesterly winds along the northern fringe of the Ural high favor warm anomalies in the Arctic. The dynamical mechanism for the connection between NESC in October and the warm Arctic-cold Eurasia (WACE) anomaly in January is further investigated from the perspective of quasi-stationary planetary wave activity. It is found that planetary waves with zonal wavenumber-1 (ZWN1) play a dominant role in this process. Specifically, the ZWN1 pattern of planetary-scale waves concurrent with October NESC anomaly extends from the surface to the upper-stratosphere. It persists in the stratosphere through November-December and propagates downward to the surface by the following January, making the connection between October NESC and January climate possible. Additionally, the influence of October NESC on the January WACE pattern has intensified since the early-2000s.

Sniff Sniff...: Your Easy Tear-Out Guide for Stopping Classroom Bugs

ERIC Educational Resources Information Center

Gelbwasser, Margaret

2007-01-01

The author's first two years of teaching were filled with read alouds, eager faces, a-ha moments, and weekends stuck at home with cold after cold. No matter how quickly she bolted from students' incoming coughs and sneezes, come winter, she always seemed to get sick again and again. Thus, in this article, the author offers ways on how to spot,…

Cold Injuries in Korea During Winter of 1950-1951

DTIC Science & Technology

1951-11-01

to be wet with perspiration (Table 7). Shoe! wAce were worn by 87.8 per cent nf patients with this condition. Am previouly irdic~tad, thii o’"ition 1...51. No informtion was available an the number of -nrr•t’ostbitten men in Korea who had a past history of cold injury. " • * k. Smoking. - Since the...inability to keep the feet warm. Cool or cold ambient t~eperatu.o% cavm.od stinging pain of the affected part. g,- B. A., a 24 year old • C, was frostbitten

A primer on clothing systems for cold-weather field work

USGS Publications Warehouse

Denner, Jon

1990-01-01

Conducting field work in cold weather is a demanding task. The most important safety consideration for field personnel is to maintain normal body temperature and avoid hypothermia.The human body adjusts to cold temperatures through different physiological processes. Heat production is enhanced by increases in the rates of basal metabolism, specific dynamic action, and physical exercise, and heat loss is reduced by vasoconstriction.Physiological adaptations alone are inadequate to stop rapid heat loss in cold temperatures. Additional insulation in the form of cold-weather clothing is necessary to retain heat.The most practical method of dressing for winter conditions is the layering system. Wearing multiple thin layers allows one to fine tune the insulation needed for different temperatures and activity levels.

Alterations in resting oxygen consumption in women exposed to 10 days of cold air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, D.W.; Thomas, J.R.

1991-03-11

Repeated exposure to cold air reduces the metabolic response to cold air exposure in man. The purpose of this investigation was to measure the change in resting metabolic rate (RMR) with exposure to 22C air and 4C air during a 12 day period. Four women sat in 22C air for 45 min followed by 45 min in 4C air each day for ten days. The authors measured RMR during a 45 min period in 22C air followed by 45 min in 4C air on four days. All subjects began their morning exposures on a Monday within 2 days of themore » onset of menses completing the study on a Friday, 12 days later. Subjects dressed in a T-shirt, shorts and cotton socks. During 45 min of exposure to warm air, RMR remained steady at 10% of VO{sub 2peak} on Day 1 and 10% on Day 5. RMR during exposure to warm air significantly increased to 13% of VO{sub 2peak} on Day 8 and remained elevated at 13% on Day 12. During exposure to cold air RMR peaked at 31% of CO{sub 2peak} by the 5th min on Day 1. Peak RMR on Day 5 was significantly lower. Pea RMR in the cold remained lower on Days 8 and 12. During cold exposure RMR peaked and then declined to steady-state during min 15 to 45. Steady-state RMR during cold exposure was significantly lower on Day 5, Day 7 and Day 12 when compared to the 23% of VO{sub 2peak} on Day 1. The authors found that RMR in cold air is significantly attenuated by Day 5 and remains lower through Day 12. RMR during warm air exposure is elevated 3% by Day 8 after five (5) days of repeated cold exposure followed by two (2) days without exposure to cold air, and RMR remains elevated on Day 12.« less

Preliminary economic analysis of aquifer winter-chill storage at the John F. Kennedy airport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, E.C.; Thomas, J.F.

A conceptual design was formulated in conjuction with a cost analysis to determine the feasibility of retrofitting the present John F. Kennedy (JFK) airport air-conditioning system with an aquifer cold water storage system. It appears technically feasible to chill and store aquifer water at the airport site during the winter months for later air-conditioning use. However, the economic analysis shows that although a significant energy savings is realized, the money saved from reduced energy costs would not be enough to recover the necessary capital investment over a 20-year period. JFK airport may be a poor economic choice for an aquifermore » cold water storage demonstration site due to site specific problems, and other sites may provide economic incentive.« less

Performance of the GEOS-3/Terra Data Assimilation System in the Northern Stratospheric Winter 1999/2000

NASA Technical Reports Server (NTRS)

Pawson, S.; Lamich, David; Ledvina, Andrea; Conaty, Austin; Newman, Paul A.; Lait, Leslie R.; Waugh, Darryn

2000-01-01

As part of NASA's support for the Terra satellite, which became operational in January 2000, the Data Assimilation Office introduced a new version of the GEOS data assimilation system (DAS) in November 1999. This system, GEOS-3/Terra, differs from its predecessor in several ways, notably through an increase in horizontal resolution (from 2-by-2.5 degrees to 1-by-1 degree), a slightly lower upper boundary (0.1 instead of 0.01hPa) with fewer levels (48 as opposed to 70), and substantial changes to the tropospheric physics package. This paper will address the performance of the GEOS-3/Terra DAS in the stratosphere. it focusses on the analyses (produced four times daily) and the five-day forecasts (produced twice daily). These were important for the meteorological support of the SAGE-3 Ozone Loss and Validation Experiment, based in Kiruna, Northern Sweden, in the winter of 1999/2000. It is shown that the analyses of basic meteorological fields (temperature, geopotential height, and horizontal wind) are in good agreement with those from other centers. The analyses captured the cold polar vortex which persisted through most of the winter. It is shown that forecasts (up to five days) tend to have a warm bias, which is important for the prediction of polar stratospheric clouds, which are triggered by temperatures of 195K (or lower). The importance of accurate upper tropospheric forecasts in predicting the stratospheric flow is highlighted in the context of the evolution of the shape of the stratospheric polar vortex. A prominent blocking high in the Atlantic region in January was an important factor determining the shape of the distorted lower stratospheric vortex; the predictive skill of these features was strongly coupled in the GEOS-3/Terra system.

The Characteristics of Cold Air Outbreaks in the Eastern United States and the Influence of Atmospheric Circulation Patterns

NASA Astrophysics Data System (ADS)

Smith, E. T.

2017-12-01

Periods of extreme cold impact the mid-latitudes every winter. Depending on the magnitude and duration of the occurrence, extremely cold periods may be deemed cold air outbreaks (CAOs). Atmospheric teleconnections impact the displacement of polar air, but the relationship between the primary teleconnections and the manifestation of CAOs is not fully understood. A systematic CAO index was developed from 20 surface weather stations based on a set of criteria concerning magnitude, duration, and spatial extent. Statistical analyses of the data were used to determine the overall trends in CAOs. Clusters of sea level pressure (SLP), 100mb, and 10mb geopotential height anomalies were mapped utilizing self-organizing maps (SOMs) to understand the surface, upper-tropospheric Polar Vortex (PV), and stratospheric PV patterns preceding CAOs. The Arctic Oscillation (AO), North Atlantic Oscillation (NAO), and Pacific-North American (PNA) teleconnections were used as variables to explain the magnitude and location of mid-latitude Arctic air displacement. Persistently negative SLP anomalies across the Arctic and North Atlantic were evident 1 - 2 weeks prior to the CAOs throughout the winter. The upper-tropospheric and stratospheric PV were found to be persistently weak/weakening prior to mid-winter CAOs and predominantly strong and off-centered prior to early and late season CAOs. Negative phases of the AO and NAO were favored prior to CAOs, while the PNA favored a near-neutral phase. This method of CAO and synoptic pattern characterization benefits from a continuous pattern representation and provides insight as to how specific teleconnections impact the atmospheric flow in a way that leads to CAOs in the eastern U.S.

Energy allocation in juvenile roach and burbot under different temperature and feeding regimes.

PubMed

Binner, Maaike; Kloas, Werner; Hardewig, Iris

2008-06-01

Cold-active burbot (Lota lota (L.)) display reduced food intake during the summer. The impact of temperature on their energy budget was investigated in starved fish in a laboratory setting, simulating summer (20 degrees C) and winter (4 degrees C) conditions, to elucidate the impact of high temperature on burbot metabolism. Metabolic effects in burbot were compared to roach (Rutilus rutilus (L.)), which typically fast in winter. During warm acclimation, starvation (four weeks) resulted in a metabolic depression of oxygen consumption in both species. In roach, metabolic rate decreased by 55% after two weeks of starvation. Burbot, in contrast, displayed an immediate depression of metabolic rate by 50%. In both species, no reductions were observed in the cold. The temperature-induced differences between the metabolic rates at 20 degrees C and 4 degrees C showed a lower thermal sensitivity in burbot (Q (10) = 1.9) compared to roach (Q (10) = 2.7). Notably, for each species, energy consumption during starvation was highest under experimental conditions simulating their natural active periods, respectively. Warm acclimated roach relied mainly on muscle reserves, whereas in cold acclimated burbot, liver metabolic stores made a major contribution to the energy turnover. In cold acclimated roach and warm acclimated burbot, however, starvation apparently reduced swimming activity, resulting in considerable savings of energy reserves. These lower energy expenditures in roach and burbot corresponded to their natural inactive periods. Thus, starvation in burbot caused a lower energy turnover when exposed to high temperatures. These season-dependent adaptations of metabolism represent an advantageous strategy in burbot to manage winter temperature and withstand metabolism-activating summer temperatures, whereas roach metabolism correlates with the seasonal temperature cycle.

Major cluster of chilblain cases in a cold dry Western Australian winter.

PubMed

Larkins, Nicholas; Murray, Kevin J

2013-02-01

Primary chilblains are an idiopathic cold-induced vasculopathy affecting the soft tissues of the hands and feet. Secondary chilblains occur in different forms of vasculitis and chronic autoimmune connective tissue disorders. Idiopathic chilblains are rarely reported in children and may generate significant anxiety to doctors and patients. We describe a cluster of idiopathic chilblains encountered over the winter of 2010 in Perth, Western Australia. This is a retrospective review of patients identified from a prospectively compiled database of all new cases seen in our department. Data on history, examination, investigations, prescribed treatments and outcomes were collected. Thirty-two patients with isolated idiopathic chilblains were included, including 20 females and 12 males with a median age at onset of 13.5 years. Lesions were papular with signs of peripheral vasoconstriction causing acrocyanosis, and uncomfortable due to pain and/or pruritis in most. Thickening of the small joints was common where lesions involved these areas. Ulceration of lesions also occurred in some. One patient required hospitalisation for secondary bacterial infection. Most received some form of treatment including non-steroidal anti-inflammatory drugs, prednisolone or nifedipine. Most patients improved spontaneously with warmer weather or responded to cold protection advice. All had resolved completely by late spring (November). Our cluster of chilblains was associated with an unusually cold winter in Perth 2010. It is the largest series reported in the literature, suggesting that chilblains may be more common than previously thought. Chilblains are almost always benign in nature and patients are systemically well and usually need no further investigation and only symptomatic treatment. Prompt recognition can avoid excessive investigation and anxiety, allowing appropriate simple advice and treatment. © 2013 The Authors. Journal of Paediatrics and Child Health © 2013 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Impacts of hot and cold temperature extremes on hospital admissions for cardiovascular diseases

NASA Astrophysics Data System (ADS)

Davídkovová, H.; Kyselý, J.; Kříž, B.

2010-09-01

Elevated mortality associated with high ambient temperatures in summer represents one of the main impacts of weather extremes on human society. Increases in mortality during heat waves were examined in many European countries; much less is known about the effects of heat waves on morbidity, measured for example by the number of hospital admissions. Relatively less understood is also cold-related mortality and morbidity in winter, when the relationships between weather and human health are more complex, less direct, and confounded by other factors such as epidemics of influenza/acute respiratory infections. The present study examines links between hot and cold temperature extremes and daily hospital admissions for cardiovascular diseases in the population of the Czech Republic over 1994-2007. We make use of a recently completed database of all admissions for cardiovascular diseases to hospitals in the area of the Czech Republic since 1994, with a detailed classification of diseases and detailed information concerning each patient (in total 1,467,675 hospital admissions over 1994-2007). The main goals of the study are (i) to identify excess/deficit morbidity during and after periods of heat waves in summer and cold spells in winter, (ii) to compare the links for individual diseases (e.g. acute myocardial infarction, I21; angina pectoris, I20; cerebral infarction, I63; brain ischemia, I64) and to identify those diagnoses that are most closely linked to weather, (iii) to identify population groups most vulnerable to temperature extremes, and (iv) to compare the links to temperature extremes for morbidity and mortality. Periods when morbidity data were affected by epidemics of influenza and acute respiratory infections in winter were excluded from the analysis.

Beyond arctic and alpine: the influence of winter climate on temperate ecosystems.

PubMed

Ladwig, Laura M; Ratajczak, Zak R; Ocheltree, Troy W; Hafich, Katya A; Churchill, Amber C; Frey, Sarah J K; Fuss, Colin B; Kazanski, Clare E; Muñoz, Juan D; Petrie, Matthew D; Reinmann, Andrew B; Smith, Jane G

2016-02-01

Winter climate is expected to change under future climate scenarios, yet the majority of winter ecology research is focused in cold-climate ecosystems. In many temperate systems, it is unclear how winter climate relates to biotic responses during the growing season. The objective of this study was to examine how winter weather relates to plant and animal communities in a variety of terrestrial ecosystems ranging from warm deserts to alpine tundra. Specifically, we examined the association between winter weather and plant phenology, plant species richness, consumer abundance, and consumer richness in 11 terrestrial ecosystems associated with the U.S. Long-Term Ecological Research (LTER) Network. To varying degrees, winter precipitation and temperature were correlated with all biotic response variables. Bud break was tightly aligned with end of winter temperatures. For half the sites, winter weather was a better predictor of plant species richness than growing season weather. Warmer winters were correlated with lower consumer abundances in both temperate and alpine systems. Our findings suggest winter weather may have a strong influence on biotic activity during the growing season and should be considered in future studies investigating the effects of climate change on both alpine and temperate systems.

Changes in apoplastic peroxidase activity and cell wall composition are associated with cold-induced morpho-anatomical plasticity of wheat leaves.

PubMed

Lorenzo, M; Pinedo, M L; Equiza, M A; Fernández, P V; Ciancia, M; Ganem, D G; Tognetti, J A

2018-02-14

Temperate grasses, such as wheat, become compact plants with small thick leaves after exposure to low temperature. These responses are associated with cold hardiness, but their underlying mechanisms remain largely unknown. Here we analyse the effects of low temperature on leaf morpho-anatomical structure, cell wall composition and activity of extracellular peroxidases, which play key roles in cell elongation and cell wall thickening, in two wheat cultivars with contrasting cold-hardening ability. A combined microscopy and biochemical approach was applied to study actively growing leaves of winter (ProINTA-Pincén) and spring (Buck-Patacón) wheat developed under constant warm (25 °C) or cool (5 °C) temperature. Cold-grown plants had shorter leaves but longer inter-stomatal epidermal cells than warm-grown plants. They had thicker walls in metaxylem vessels and mestome sheath cells, paralleled with accumulation of wall components, predominantly hemicellulose. These effects were more pronounced in the winter cultivar (Pincén). Cold also induced a sharp decrease in apoplastic peroxidase activity within the leaf elongating zone of Pincén, and a three-fold increase in the distal mature zone of the leaf. This was consistent with the enhanced cell length and thicker cell walls in this cultivar at 5 °C. The different response to low temperature of apoplastic peroxidase activity and hemicellulose between leaf zones and cultivar types suggests they might play a central role in the development of cold-induced compact morphology and cold hardening. New insights are presented on the potential temperature-driven role of peroxidases and hemicellulose in cell wall dynamics of grasses. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Hypertension Does Not Alter the Increase in Cardiac Baroreflex Sensitivity Caused by Moderate Cold Exposure

PubMed Central

Hintsala, Heidi E.; Kiviniemi, Antti M.; Tulppo, Mikko P.; Helakari, Heta; Rintamäki, Hannu; Mäntysaari, Matti; Herzig, Karl-Heinz; Keinänen-Kiukaanniemi, Sirkka; Jaakkola, Jouni J. K.; Ikäheimo, Tiina M.

2016-01-01

Exposure to cold increases blood pressure and may contribute to higher wintertime cardiovascular morbidity and mortality in hypertensive people, but the mechanisms are not well-established. While hypertension does not alter responses of vagally-mediated heart rate variability to cold, it is not known how hypertension modifies baroreflex sensitivity (BRS) and blood pressure variability during cold exposure. Our study assessed this among untreated hypertensive men during short-term exposure comparable to habitual winter time circumstances in subarctic areas. We conducted a population-based recruitment of 24 untreated hypertensive and 17 men without hypertension (age 55–65 years) who underwent a whole-body cold exposure (−10°C, wind 3 m/s, winter clothes, 15 min, standing). Electrocardiogram and continuous blood pressure were measured to compute spectral powers of systolic blood pressure and heart rate variability at low (0.04–0.15 Hz) and high frequency (0.15–0.4 Hz) and spontaneous BRS at low frequency (LF). Comparable increases in BRS were detected in hypertensive men, from 2.6 (2.0, 4.2) to 3.8 (2.5, 5.1) ms/mmHg [median (interquartile range)], and in control group, from 4.3 (2.7, 5.0) to 4.4 (3.1, 7.1) ms/mmHg. Instead, larger increase (p < 0.05) in LF blood pressure variability was observed in control group; response as median (interquartile range): 8 (2, 14) mmHg2, compared with hypertensive group [0 (−13, 20) mmHg2]. Untreated hypertension does not disturb cardiovascular protective mechanisms during moderate cold exposure commonly occurring in everyday life. Blunted response of the estimate of peripheral sympathetic modulation may indicate higher tonic sympathetic activity and decreased sympathetic responsiveness to cold in hypertension. PMID:27313543

Characterizing soil moisture and snow cover effects on boreal-arctic soil freeze/thaw dynamics and cold-season carbon emissions

NASA Astrophysics Data System (ADS)

Yi, Y.; Kimball, J. S.; Moghaddam, M.; Chen, R. H.; Reichle, R. H.; Oechel, W. C.; Zona, D.

2017-12-01

The contribution of cold season respiration to boreal-arctic carbon cycle and its potential feedbacks to climate change remain poorly quantified. Here, we developed an integrated modeling framework combining airborne low frequency (L+P-band) airborne radar retrievals and landscape level (≥1km) environmental observations from satellite optical and microwave sensors with a detailed permafrost carbon model to investigate underlying processes controlling soil freeze/thaw (FT) dynamics and cold season carbon emissions. The permafrost carbon model simulates the snow and soil thermal dynamics with soil water phase change included and accounts for soil carbon decomposition up to 3m below surface. Local-scale ( 50m) radar retrievals of active layer thickness (ALT), soil moisture and freeze/thaw (FT) status from NASA airborne UAVSAR and AirMOSS sensors are used to inform the model parameterizations of soil moisture effects on soil FT dynamics, and scaling properties of active layer processes. Both tower observed land-atmosphere fluxes and atmospheric CO2 measurements are used to evaluate the model processes controlling cold season carbon respiration, particularly the effects of snow cover and soil moisture on deep soil carbon emissions during the early cold season. Initial comparisons showed that the model can well capture the seasonality of cold season respiration in both tundra and boreal forest areas, with large emissions in late fall and early winter and gradually diminishing throughout the winter. Model sensitivity analyses are used to clarify how changes in soil thermodynamics at depth control the magnitude and seasonality of cold season respiration, and how a deeper unfrozen active layer with warming may contribute to changes in cold season respiration. Model outputs include ALT and regional carbon fluxes at 1-km resolution spanning recent satellite era (2001-present) across Alaska. These results will be used to quantify cold season respiration contributions to the annual carbon cycle and help close the boreal-arctic annual carbon budget.

National Weather Service

MedlinePlus

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Cold Fusion.

ERIC Educational Resources Information Center

Dutton, Eileen; Salazar, Chris

1998-01-01

Discusses ways of preparing school-building roofs for the winter season by paying attention to common problem areas. Also highlights the use of white elastomeric roof coatings, their benefits, and considerations when applying them. (GR)

Winter precipitation changes during the Medieval Climate Anomaly and the Little Ice Age in arid Central Asia

NASA Astrophysics Data System (ADS)

Fohlmeister, Jens; Plessen, Birgit; Dudashvili, Alexey Sergeevich; Tjallingii, Rik; Wolff, Christian; Gafurov, Abror; Cheng, Hai

2017-12-01

The strength of the North Atlantic Oscillation (NAO) is considered to be the main driver of climate changes over the European and western Asian continents throughout the last millennium. For example, the predominantly warm Medieval Climate Anomaly (MCA) and the following cold period of the Little Ice Age (LIA) over Europe have been associated with long-lasting phases with a positive and negative NAO index. Its climatic imprint is especially pronounced in European winter seasons. However, little is known about the influence of NAO with respect to its eastern extent over the Eurasian continent. Here we present speleothem records (δ13C, δ18O and Sr/Ca) from the southern rim of Fergana Basin (Central Asia) revealing annually resolved past climate variations during the last millennium. The age control of the stalagmite relies on radiocarbon dating as large amounts of detrital material inhibit accurate 230Th dating. Present-day calcification of the stalagmite is most effective during spring when the cave atmosphere and elevated water supply by snow melting and high amount of spring precipitation provide optimal conditions. Seasonal precipitation variations cause changes of the stable isotope and Sr/Ca compositions. The simultaneous changes in these geochemical proxies, however, give also evidence for fractionation processes in the cave. By disentangling both processes, we demonstrate that the amount of winter precipitation during the MCA was generally higher than during the LIA, which is in line with climatic changes linked to the NAO index but opposite to the higher mountain records of Central Asia. Several events of strongly reduced winter precipitation are observed during the LIA in Central Asia. These dry winter events can be related to phases of a strong negative NAO index and all results reveal that winter precipitation over the central Eurasian continent is tightly linked to atmospheric NAO modes by the westerly wind systems.

Nutrition for winter sports.

PubMed

Meyer, Nanna L; Manore, Melinda M; Helle, Christine

2011-01-01

Winter sports are played in cold conditions on ice or snow and often at moderate to high altitude. The most important nutritional challenges for winter sport athletes exposed to environmental extremes include increased energy expenditure, accelerated muscle and liver glycogen utilization, exacerbated fluid loss, and increased iron turnover. Winter sports, however, vary greatly regarding their nutritional requirements due to variable physiological and physique characteristics, energy and substrate demands, and environmental training and competition conditions. What most winter sport athletes have in common is a relatively lean physique and high-intensity training periods, thus they require greater energy and nutrient intakes, along with adequate food and fluid before, during, and after training. Event fuelling is most challenging for cross-country skiers competing in long events, ski jumpers aiming to reduce their body weight, and those winter sport athletes incurring repeated qualification rounds and heats. These athletes need to ensure carbohydrate availability throughout competition. Finally, winter sport athletes may benefit from dietary and sport supplements; however, attention should be paid to safety and efficacy if supplementation is considered.

Susceptibility to mortality related to temperature and heat and cold wave duration in the population of Stockholm County, Sweden

PubMed Central

Rocklöv, Joacim; Forsberg, Bertil; Ebi, Kristie; Bellander, Tom

2014-01-01

Background Ambient temperatures can cause an increase in mortality. A better understanding is needed of how health status and other factors modify the risk associated with high and low temperatures, to improve the basis of preventive measures. Differences in susceptibility to temperature and to heat and cold wave duration are relatively unexplored. Objectives We studied the associations between mortality and temperature and heat and cold wave duration, stratified by age and individual and medical factors. Methods Deaths among all residents of Stockholm County between 1990 and 2002 were linked to discharge diagnosis data from hospital admissions, and associations were examined using the time stratified case-crossover design. Analyses were stratified by gender, age, pre-existing disease, country of origin, and municipality level wealth, and adjusted for potential confounding factors. Results The effect on mortality by heat wave duration was higher for lower ages, in areas with lower wealth, for hospitalized patients younger than age 65. Odds were elevated among females younger than age 65, in groups with a previous hospital admission for mental disorders, and in persons with previous cardiovascular disease. Gradual increases in summer temperatures were associated with mortality in people older than 80 years, and with mortality in groups with a previous myocardial infarction and with chronic obstructive pulmonary disease (COPD) in the population younger than 65 years. During winter, mortality was associated with a decrease in temperature particularly in men and with the duration of cold spells for the population older than 80. A history of hospitalization for myocardial infarction increased the odds associated with cold temperatures among the population older than 65. Previous mental disease or substance abuse increased the odds of death among the population younger than 65. Conclusion To increase effectiveness, we suggest preventive efforts should not assume susceptible groups are the same for warm and cold days and heat and cold waves, respectively. PMID:24647126

Does Day Length Affect Winter Bird Distribution? Testing the Role of an Elusive Variable

PubMed Central

Carrascal, Luis M.; Santos, Tomás; Tellería, José L.

2012-01-01

Differences in day length may act as a critical factor in bird biology by introducing time constraints in energy acquisition during winter. Thus, differences in day length might operate as a main determinant of bird abundance along latitudinal gradients. This work examines the influence of day length on the abundance of wintering crested tits (Lophophanes cristatus) in 26 localities of Spanish juniper (Juniperus thurifera) dwarf woodlands (average height of 5 m) located along a latitudinal gradient in the Spanish highlands, while controlling for the influence of food availability, minimum night temperature, habitat structure and landscape characteristics. Top regression models in the AIC framework explained 56% of variance in bird numbers. All models incorporated day length as the variable with the highest magnitude effect. Food availability also played an important role, although only the crop of ripe juniper fruits, but not arthropods, positively affected crested tit abundance. Differences in vegetation structure across localities had also a strong positive effect (average tree height and juniper tree density). Geographical variation in night temperature had no influence on crested tit distribution, despite the low winter temperatures reached in these dwarf forests. This paper demonstrates for the first time that winter bird abundance increases with day length after controlling for the effect of other environmental variables. Winter average difference in day length was only 10.5 minutes per day along the 1°47′ latitudinal interval (190 km) included in this study. This amount of time, which reaches 13.5 h accumulated throughout the winter season, appears to be large enough to affect the long-term energy budget of small passerines during winter and to shape the distribution of winter bird abundance under restrictive environmental conditions. PMID:22393442

Features of Creation and Operation of Electric and Hybrid Vehicles in Countries with Difficult Climatic Conditions, for Example, in the Russian Federation

NASA Astrophysics Data System (ADS)

Karpukhin, K.; Terenchenko, A.

2016-11-01

The trend of increasing fleet of electric or hybrid vehicles and determines the extension of the geographical areas of operation, including the Northern areas with cold winter weather. Practically in all territory of Russia the average winter temperature is negative. With the winter temperatures can be below in Moscow -30°C, in Krasnoyarsk -50°C. Battery system can operate in a wide temperature range, but there are extremes that should be remembered all the time, especially in cold climates like Russia. In the operating instructions of the electric car Tesla Model S indicate that to save the battery don't use at temperatures below -15°C. The paper presents the dependence of the cooling time and heating of the battery cell at different ambient temperatures and provides guidance on allowable cooling time while using and not thermally insulated thermally containers Suggests using the temperature control on the basis of thermoelectric converters Peltier connection from the onboard electrical network of the electric vehicle.

The tolerance of the field slug Deroceras reticulatum to freezing temperatures.

PubMed

Cook, R T

2004-01-01

Cold hardiness of ectotherms has been widely studied in arthropods, but there is a more limited literature on the survival of molluscs at low temperatures. A number of intertidal species have been examined in detail, but terrestrial molluscs have largely been overlooked until recently. This paper reports results of laboratory experiments to evaluate the cold hardiness of the terrestrial slug, Deroceras reticulatum. The mean supercooling point (SCP) rose from -4.2 degree C in summer to -3.6 degree C in winter. The SCP that caused 50 percent mortality (LSCP50) remained constant at -4.7 to -4.8 degree C in both seasons, but slugs were able to survive the frozen state for longer in winter (LD50 of 31.8 minutes compared with 17.0 minutes in summer). Slug survival at freezing temperatures was prolonged to at least five hours when placed on a moist, absorbent substrate. D. reticulatum exhibits partial freeze tolerance, with an increased survival in winter. The results are discussed in relation to the natural environment of slugs.

Conditions to generate Steam Fog Occurred around the Chungju Lake in the South Korea

NASA Astrophysics Data System (ADS)

Byungwoo, J.

2017-12-01

We have collected the field observation data of the steam fog occurred around the Chungju Lake in the South Korea for 3 years(2014 2016) and analyzed conditions in which the steam fog occurred. The Chungju Lake is an artificial lake made by the Chungju Dam with a water storage of 2.7 billion tons, which is the second largest in South Korea. The Chungju Dam have discharged water of the average 2.2 million tons downstream to produce electricity per day. The drainage water heats downstream of the Chungju dam and the air above water surface of downstream of that. When the warm, humid air above the downstream water mixed with cold air mass, it caused "steam fog" around the downstream of Chungju lake regardless of amount of the discharged water. The condition that promote the generation of steam fog in autumn and winter is as follows: (1) cloudless night with light winds below 1.5 m/s. (2) The differences between the temperature of discharged water from the Chungju Dam and the air temperature above the discharged water varied from 3° to 15° in autumn, from 15° to 20° in winter respectively. (3) When stream fog was generated, sensible heat flux ranged in autumn from 5 to 15 W/m2, in winter from 15 to 20 W/m2 respectively. Latent heat flux ranged in autumn from 15 to 20 W/m2, in winter from 10 to 15 W/m2 respectively.

Tendencies of extreme values on rainfall and temperature and its relationship with teleconnection patterns

NASA Astrophysics Data System (ADS)

Taboada, J. J.; Cabrejo, A.; Guarin, D.; Ramos, A. M.

2009-04-01

It is now very well established that yearly averaged temperatures are increasing due to anthropogenic climate change. In the area of Galicia (NW Spain) this trend has also been determined. Rainfall does not show a clear tendency in its yearly accumulated values. The aim of this work is to study different extreme indices of rainfall and temperatures analysing variability and possible trends associated to climate change. Station data for the study was provided by the CLIMA database of the regional government of Galicia (NW Spain). The definition of the extreme indices was taken from the joint CCl/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices (ETCCDI) This group has defined a set of standard extreme values to simplify intercomparison of data from different regions of the world. For the temperatures in the period 1960-2006, results show a significant increase of the number of days with maximum temperatures above the 90th percentile. Furthermore, a significant decrease of the days with maximum temperatures below the 10th percentile has been found. The tendencies of minimum temperatures are reverse: fewer nights with minimum temperatures below 10th percentile, and more with minimum temperatures above 90th percentile. Those tendencies can be observed all over the year, but are more pronounced in summer. This trend is expected to continue in the next decades because of anthropogenic climate change. We have also calculated the relationship between the above mentioned extreme values and different teleconnection patterns appearing in the North Atlantic area. Results show that local tendencies are associated with trends of EA (Eastern Atlantic) and SCA (Scandinavian) patterns. NAO (North Atlantic Oscillation) has also some relationship with these tendencies, but only related with cold days and nights in winter. Rainfall index do not show any clear tendency on the annual scale. Nevertheless, the count of days when precipitation is greater than 20mm (R20mm) and the total precipitation when rainfall is greater than 95th percentile (R95pTOT) diminishes in winter and spring, but increases in autumn. This trend is related with NAO in winter and spring and with SCA in autumn.

Update: cold weather injuries, active and reserve components, U.S. Armed Forces, July 2009-June 2014.

PubMed

Connor, Ricardford R

2014-10-01

From July 2013 through June 2014, the number of active and reserve component service members treated for cold injuries (n=719) was the highest of the past five cold seasons (2009-2014). The rate of cold injury among active component personnel was also the highest of the 5-year period. Army personnel accounted for the majority (62%) of cold injuries. Frostbite was the most common type of cold injury in each of the services. Consistent with trends from previous cold seasons, service members who were female, younger than 20 years old, or of black, non-Hispanic race/ethnicity tended to have higher cold injury rates than their respective counterparts. Numbers of cases in the combat zone have decreased in the past 2 years, presumably as a result of declining numbers of personnel exposed and the changing nature of operations. The increase in numbers and the geographic distribution of cold injuries in the previous cold season are compatible with the unusual pattern of cold weather that marked Winter 2013-2014.

Transcriptome Profiling of the Pineapple under Low Temperature to Facilitate Its Breeding for Cold Tolerance

PubMed Central

Chen, Chengjie; Zhang, Yafeng; Xu, Zhiqiang; Luan, Aiping; Mao, Qi; Feng, Junting; Xie, Tao; Gong, Xue; Wang, Xiaoshuang; Chen, Hao; He, Yehua

2016-01-01

The pineapple (Ananas comosus) is cold sensitive. Most cultivars are injured during winter periods, especially in sub-tropical regions. There is a lack of molecular information on the pineapple’s response to cold stress. In this study, high-throughput transcriptome sequencing and gene expression analysis were performed on plantlets of a cold-tolerant genotype of the pineapple cultivar ‘Shenwan’ before and after cold treatment. A total of 1,186 candidate cold responsive genes were identified, and their credibility was confirmed by RT-qPCR. Gene set functional enrichment analysis indicated that genes related to cell wall properties, stomatal closure and ABA and ROS signal transduction play important roles in pineapple cold tolerance. In addition, a protein association network of CORs (cold responsive genes) was predicted, which could serve as an entry point to dissect the complex cold response network. Our study found a series of candidate genes and their association network, which will be helpful to cold stress response studies and pineapple breeding for cold tolerance. PMID:27656892

Cloning of heat shock protein genes (hsp70, hsc70 and hsp90) and their expression in response to larval diapause and thermal stress in the wheat blossom midge, Sitodiplosis mosellana.

PubMed

Cheng, Weining; Li, Dan; Wang, Yue; Liu, Yang; Zhu-Salzman, Keyan

2016-12-01

Sitodiplosis mosellana Géhin, one of the most important pests of wheat, undergoes obligatory diapause as a larva to survive unfavorable temperature extremes during hot summers and cold winters. To explore the potential roles of heat shock proteins (hsp) in this process, we cloned full-length cDNAs of hsp70, hsc70 and hsp90 from S. mosellana larvae, and examined their expression in response to diapause and short-term temperature stresses. Three hsps included all signature sequences of corresponding protein family and EEVD motifs. They showed high homology to their counterparts in other species, and the phylogenetic analysis of hsp90 was consistent with the known classification of insects. Expression of hsp70 and hsp90 were highly induced by diapause, particularly pronounced during summer and winter. Interestingly, hsp70 was more strongly expressed in summer than in winter whereas hsp90 displayed the opposite pattern. Abundance of hsc70 mRNA was comparable prior to and during diapauses and was highly up-regulated when insects began to enter the stage of post-diapause quiescence. Heat-stressed over-summering larvae (⩾30°C) or cold-stressed over-wintering larvae (⩽0°C) could further elevate expression of these three genes, but temperature extremes i.e. as high as 45°C or as low as -15°C failed to trigger such expression patterns. Notably, hsp70 was most sensitive to heat stress and hsp90 was most sensitive to cold stress. These results suggested that hsp70 and hsp90 play key roles in diapause maintenance and thermal stress; the former may be more prominent contributor to heat tolerance and the latter for cold tolerance. In contrast, hsc70 most likely is involved in developmental transition from diapause to post-diapause quiescence, and thus may serve as a molecular marker to predict diapause termination. Copyright © 2016 Elsevier Ltd. All rights reserved.

Induction of cold hardiness in an invasive herbivore: The case of hemlock woolly adelgid (Hemiptera: Adelgidae)

Treesearch

Joseph S. Elkinton; Jeffrey A. Lombardo; Artemis D. Roehrig; Thomas J. McAvoy; Albert Mayfield; Mark Whitmore

2017-01-01

As a measure of cold hardiness, we tested the supercooling points or freezing temperatures of individual hemlock woolly adelgids (Adelges tsugae Annand) collected from 15 locations across the north to south range of the adelgid in eastern North America at different times during two winters. Adelgids from the northern interior locations with USDA hardiness zones of 5B–...

Effects of calcium fertilization and acid mist on calcium concentration and cold tolerance of red spruce needles

Treesearch

G. R. Strimbeck; David R. Vann; Arthur H. Johnson

1996-01-01

Several studies have shown that exposure to acid mist impairs cold tolerance of red spruce foliage, predisposing it to winter injury, which appears to be a major factor in the decline of montane populations of the species. Other studies have shown increases in calcium (Ca) concentration in canopy throughfall in montane spruce-fir forests, and decreases in foliar Ca...

Winter frost at Viking Lander 2 site

NASA Technical Reports Server (NTRS)

Svitek, Thomas; Murray, Bruce

1990-01-01

This paper presents quantitative evidence for cold trapping (frost redeposition) at the Viking Lander 2 site. This evidence consists of the frost surface coverage and color transition, the timing of this transition, and the limited vertical mixing and horizontal water transport. It is argued that cold trapping must be a general property of seasonal frost and, therefore, must be considered in order to understand the evolution of the surface environment of Mars.

ENSO's far reaching connection to Indian cold waves.

PubMed

Ratnam, J V; Behera, Swadhin K; Annamalai, H; Ratna, Satyaban B; Rajeevan, M; Yamagata, Toshio

2016-11-23

During boreal winters, cold waves over India are primarily due to transport of cold air from higher latitudes. However, the processes associated with these cold waves are not yet clearly understood. Here by diagnosing a suite of datasets, we explore the mechanisms leading to the development and maintenance of these cold waves. Two types of cold waves are identified based on observed minimum surface temperature and statistical analysis. The first type (TYPE1), also the dominant one, depicts colder than normal temperatures covering most parts of the country while the second type (TYPE2) is more regional, with significant cold temperatures only noticeable over northwest India. Quite interestingly the first (second) type is associated with La Niña (El Niño) like conditions, suggesting that both phases of ENSO provide a favorable background for the occurrence of cold waves over India. During TYPE1 cold wave events, a low-level cyclonic anomaly generated over the Indian region as an atmospheric response to the equatorial convective anomalies is seen advecting cold temperatures into India and maintaining the cold waves. In TYPE2 cold waves, a cyclonic anomaly generated over west India anomalously brings cold winds to northwest India causing cold waves only in those parts.

Spatial distribution of cold-season lightning frequency in the coastal areas of the Sea of Japan

NASA Astrophysics Data System (ADS)

Tsurushima, Daiki; Sakaida, Kiyotaka; Honma, Noriyasu

2017-12-01

The coastal areas of the Sea of Japan are a well-known hotspot of winter lightning activity. This study distinguishes between three common types of winter lightning in that region (types A-C), based on their frequency distributions and the meteorological conditions under which they occur. Type A lightning occurs with high frequency in the Tohoku district. It is mainly caused by cold fronts that accompany cyclones passing north of the Japanese islands. Type B, which occurs most frequently in the coastal areas of the Hokuriku district, is mainly caused by topographically induced wind convergence and convective instability, both of which are associated with cyclones having multiple centers. Type C's lightning frequency distribution pattern is similar to that of type B, but its principal cause is a topographically induced wind convergence generated by cold air advection from the Siberian continent. Type A is most frequently observed from October to November, while types B and C tend to appear from November to January, consistent with seasonal changes in lightning frequency distribution in Japan's Tohoku and Hokuriku districts.

Warm Arctic-cold Siberia: comparing the recent and the early 20th-century Arctic warmings

NASA Astrophysics Data System (ADS)

Wegmann, Martin; Orsolini, Yvan; Zolina, Olga

2018-02-01

The Warm Arctic-cold Siberia surface temperature pattern during recent boreal winter is suggested to be triggered by the ongoing decrease of Arctic autumn sea ice concentration and has been observed together with an increase in mid-latitude extreme events and a meridionalization of tropospheric circulation. However, the exact mechanism behind this dipole temperature pattern is still under debate, since model experiments with reduced sea ice show conflicting results. We use the early twentieth-century Arctic warming (ETCAW) as a case study to investigate the link between September sea ice in the Barents-Kara Sea (BKS) and the Siberian temperature evolution. Analyzing a variety of long-term climate reanalyses, we find that the overall winter temperature and heat flux trend occurs with the reduction of September BKS sea ice. Tropospheric conditions show a strengthened atmospheric blocking over the BKS, strengthening the advection of cold air from the Arctic to central Siberia on its eastern flank, together with a reduction of warm air advection by the westerlies. This setup is valid for both the ETCAW and the current Arctic warming period.

A Longitudinal Study of Disease Incidence among Antarctic Winter-Over Personnel.

DTIC Science & Technology

1986-02-01

follow-up study of enlisted Navy personnel found no long-term risk for first hospital admissions. " Objective The objective of this study was to test ...the Antarctic winter and demographic. personality, and socioenvironmental factors which mediate the physical and psychological stress associated with...over personnel are at risk for disease and psychological stress upon their return to the outside world. Outbreaks of common colds have been noted among

The Case for CASES

ERIC Educational Resources Information Center

Powell, W. R.

1978-01-01

In this article the Community Annual Energy Storage System ( CASES), a "thermal utility" plan for heating and cooling communities by storing summer heat and winter cold for use in the opposite season, is described. (MDR)

Potassium and Your CKD Diet

MedlinePlus

... ¼ whole) Artichoke Chocolate (1.5-2 ounces) Banana (½ whole) Bamboo Shoots Granola Cantaloupe Baked Beans ... Sweet Potatoes, Carrots, Beets, Winter Squash, and Rutabagas: Peel and place the vegetable in cold water so ...

Large Scale Drivers for the Extreme Storm Season over the North Atlantic and the UK in Winter 2013-14

NASA Astrophysics Data System (ADS)

Wild, Simon; Befort, Daniel J.; Leckebusch, Gregor C.

2016-04-01

The British Isles experienced exceptional stormy and rainy weather conditions in winter 2013-2014 while large parts of central North America recorded near record minimum surface temperatures values. Potential drivers for these cold conditions include increasingly warm surface waters of the tropical west Pacific. It has been suggested these increasing sea surface temperatures could also be the cause for extreme weather over the Europe, particularly the UK. Testing this hypothesis, we investigate mechanisms linking the tropical west Pacific and European wind storm activity. We will firstly analyse anomaly patterns along such a potential link in winter 2013-14. Secondly, we will investigate whether these identified anomaly patterns show a strong interannual relationship in the recent past. Our results, using primarily ERA-Interim Reanalysis from 1979 to 2014, show an absolute maximum of wind storm frequency over the northeast Atlantic and the British Isles in winter 2013-14. We also find absolute minimum surface temperatures in central North America and increased convective activity over the tropical west Pacific in the same season. The winter 2013-14 was additionally characterized by anomalous warm sea surface temperatures over the subtropical northwest Atlantic. Although the interannual variability of wind storms in the northeast Atlantic and surface temperatures in North America are significantly anti-correlated, we cannot directly relate wind storm frequency with tropical west Pacific anomalies. We thus conclude that the conditions over the Pacific in winter 2013-14 were favourable but not sufficient to explain the record number of wind storms in this season. Instead, we suggest that warm north Atlantic sea surface temperature anomalies in combination with cold surface temperatures over North America played a more important role for generating higher wind storm counts over the northeast Atlantic and the UK.

Distribution of Different Biogeographical Tintinnids in Yellow Sea and Bohai Sea

NASA Astrophysics Data System (ADS)

Chen, Xue; Li, Haibo; Zhao, Yuan; Zhao, Li; Dong, Yi; Zhang, Wuchang; Xiao, Tian

2018-04-01

There were different biogeographical tintinnids in the oceans. Knowledge of their distribution pattern and mixing was important to the understanding of ecosystem functions. Yellow Sea (YS) and Bohai Sea (BS) were semi-enclosed seas influenced by warm water intrusion and YS cold bottom water. The occurrence of tintinnids in YS and BS during two cruises (summer and winter) were investigated to find out: i) whether warm-water tintinnids appeared in YS and BS; ii) whether boreal tintinnids appeared in high summer; iii) the core area of neritic tintinnids and iv) how these different biogeographical tintinnids mixed. Our results showed that tintinnid community was dominated by neritic tintinnid. We confirmed the occurrence of warm-water tintinnids in summer and winter. In summer, they intruded into BS and mainly distributed in the upper 20 m where Yellow Sea Surface Warm Water (YSSWW) developed. In winter, they were limited in the surface water of central deep region (bottom depth >50 m) of YS where were affected by Yellow Sea Warm Water (YSWW). Boreal tintinnids occurred in YS in high summer (August) and in winter, while they were not observed in BS. In summer, the highest abundance of boreal tintinnids occurred in Yellow Sea Bottom Cold Water, indicating the presence of an oversummering stock. In winter, they were concentrated in the north of YSWW. Vertically, neritic tintinnids abundance was high in the bottom layers. Horizontally, high neritic tintinnids abundance in bottom layers occurred along the 50 m isobath coinciding with the position of front systems. Front systems were the core distribution area of neritic tintinnids. High abundance areas of warm-water and boreal tintinnids were clearly separated vertically in summer, and horizontally in winter. High abundance of neritic tintinnids rarely overlapped with that of warm-water or boreal tintinnids.

Climatic variability and plant food distribution in Pleistocene Europe: Implications for Neanderthal diet and subsistence

NASA Astrophysics Data System (ADS)

Hardy, Bruce L.

2010-03-01

Contrary to their cold-adapted image, Neanderthals inhabited Pleistocene Europe during a time of great climatic fluctuation with temperatures ranging from as warm as present-day during the last interglacial to as cold as those of the last glacial maximum. Cold-adapted Neanderthals are similarly most often associated with the exploitation of large mammals who are themselves cold-adapted (mammoth, bison, reindeer, etc.). Cold, high-latitude environments are typically seen as lacking in plants generally and in plant foods in particular. Plant foods are therefore usually ignored and Neanderthals are increasingly being viewed as top carnivores who derived the vast majority of their diet from meat. Support for this hypothesis comes largely from stable isotope analysis which tracks only the protein portion of the diet. Diets high in lean meat largely fulfill micronutrient needs but can pose a problem at the macronutrient level. Lean meat can compose no more than 35% of dietary energy before a protein ceiling is reached. Exceeding the protein ceiling can have detrimental physiological effects on the individual. Neanderthals would have needed energy from alternative sources, particularly when animals are fat-depleted and lean meat intake is high. Underground storage organs (USOs) of plants offer one such source, concentrating carbohydrates and energy. USOs could also provide an important seasonal energy source since they are at their maximum energy storage in late fall/winter. Although Paleolithic sites are increasingly yielding plant remains, their presence is rare and they are often given only passing mention in Neanderthal dietary reconstructions. The complexity and number of potential wild plant foods, however, defies easy discussion. Native European wild edible plants with starchy USOs would have been potentially available throughout the Neanderthal range, even during the coldest periods of the Late Pleistocene.

High-Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States

NASA Astrophysics Data System (ADS)

Zobel, Zachary; Wang, Jiali; Wuebbles, Donald J.; Kotamarthi, V. Rao

2017-12-01

The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary conditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal-length time slices (2045-2054 and 2085-2094) are compared with a historical decade (1995-2004). Probability density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm-side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm-side shift with decreased variability. Using "business-as-usual" scenario, 5-day heat waves are projected to occur at least 5-10 times per year in most CONUS and ≥95°F days will increase by 1-2 months by the end of the century.

Role of cold water and beta-effect in the formation of the East Korean Warm Current in the East/Japan Sea: a numerical experiment

NASA Astrophysics Data System (ADS)

Kim, Yong-Yub; Cho, Yang-Ki; Kim, Young Ho

2018-06-01

The contributions of bottom cold water and planetary β-effect to the formation of the East Korean Warm Current (EKWC), the western boundary current in the East/Japan Sea (EJS), were evaluated using an idealized three-dimensional numerical model. The model results suggest that the bottom cold water and, to a lesser extent, the planetary β-effect both contribute to the formation of the EKWC. The cold water functions as the bottom of the upper layer, to control the EKWC via conservation of potential vorticity. It is known that cold waters, such as the North Korean Cold Water and Korea Strait Bottom Cold Water often observed during summer along the southwestern coast of the EJS, originate from the winter convection in the northern area. Observational studies consistently show that the EKWC strengthens in summer when the cold water extends further south along the western boundary.

Ecosystem warming increases sap flow rates of northern red oak trees

DOE PAGES

Juice, Stephanie M.; Templer, Pamela H.; Phillips, Nathan G.; ...

2016-03-17

Over the next century, air temperature increases up to 5°C are projected for the northeastern United States. As evapotranspiration strongly influences water loss from terrestrial ecosystems, the ecophysiological response of trees to warming will have important consequences for forest water budgets. We measured growing season sap flow rates in mature northern red oak ( Quercus rubra L.) trees in a combined air (up to 5.5°C above ambient) and soil (up to 1.85°C above ambient at 6-cm depth) warming experiment at Harvard Forest, Massachusetts, United States. Through principal components analysis, we found air and soil temperatures explained the largest amount ofmore » variance in environmental variables associated with rates of sap flow, with relative humidity, photosynthetically active radiation and vapor pressure deficit having significant, but smaller, effects. On average, each 1°C increase in temperature increased sap flow rates by approximately 1100 kg H 2O m -2 sapwood area day-1 throughout the growing season and by 1200 kg H 2O m -2 sapwood area day -1 during the early growing season. Reductions in the number of cold winter days correlated positively with increased sap flow during the early growing season (a decrease in 100 heating-degree days was associated with a sapflow increase in approximately 5 kg H 2O m -2 sapwood area day -1). Soil moisture declined with increased treatment temperatures, and each soil moisture percentage decrease resulted in a decrease in sap flow of approximately 360 kg H2O m -22 sapwood area day -1. At night, soil moisture correlated positively with sap flow. Finally, these results demonstrate that warmer air and soil temperatures in winter and throughout the growing season lead to increased sap flow rates, which could affect forest water budgets throughout the year.« less

Ecosystem warming increases sap flow rates of northern red oak trees

DOE Office of Scientific and Technical Information (OSTI.GOV)

Juice, Stephanie M.; Templer, Pamela H.; Phillips, Nathan G.

Over the next century, air temperature increases up to 5°C are projected for the northeastern United States. As evapotranspiration strongly influences water loss from terrestrial ecosystems, the ecophysiological response of trees to warming will have important consequences for forest water budgets. We measured growing season sap flow rates in mature northern red oak ( Quercus rubra L.) trees in a combined air (up to 5.5°C above ambient) and soil (up to 1.85°C above ambient at 6-cm depth) warming experiment at Harvard Forest, Massachusetts, United States. Through principal components analysis, we found air and soil temperatures explained the largest amount ofmore » variance in environmental variables associated with rates of sap flow, with relative humidity, photosynthetically active radiation and vapor pressure deficit having significant, but smaller, effects. On average, each 1°C increase in temperature increased sap flow rates by approximately 1100 kg H 2O m -2 sapwood area day-1 throughout the growing season and by 1200 kg H 2O m -2 sapwood area day -1 during the early growing season. Reductions in the number of cold winter days correlated positively with increased sap flow during the early growing season (a decrease in 100 heating-degree days was associated with a sapflow increase in approximately 5 kg H 2O m -2 sapwood area day -1). Soil moisture declined with increased treatment temperatures, and each soil moisture percentage decrease resulted in a decrease in sap flow of approximately 360 kg H2O m -22 sapwood area day -1. At night, soil moisture correlated positively with sap flow. Finally, these results demonstrate that warmer air and soil temperatures in winter and throughout the growing season lead to increased sap flow rates, which could affect forest water budgets throughout the year.« less

Validity and reproducibility of a food frequency questionnaire for assessment of fruit and vegetable intake in Iranian adults*

PubMed Central

Mohammadifard, Noushin; Omidvar, Nasrin; Houshiarrad, Anahita; Neyestani, Tirang; Naderi, Gholam-Ali; Soleymani, Bahram

2011-01-01

BACKGROUND: This study's aim was to design and validate a semi-quantitative food frequency questionnaire (FFQ) for assessment of fruits and vegetables (FV) consumption in adults of Isfahan by comparing the FFQ with dietary reference method and blood plasma levels of beta-carotene, vitamin C, and retinol. METHODS: This validation study was performed on 123 healthy adults of Isfahan. FV intake was assessed using a 110-item FFQ. Data collection was performed during two different time periods to control for seasonal effects, fall/winter (cold season) and spring/summer (warm season). In each phase a FFQ and 1 day recall, and 2 days of food records as the dietary reference method were completed and plasma vitamin C, beta-carotene and retinol were measured. Data was analyzed by Pearson or Spearman and intraclass correlations. RESULTS: Serum Lipids, sex, age, body mass index (BMI) and educational level adjusted Pearson correlation coefficient of FV with plasma vitamin C, beta-carotene and retinol were 0.55, 0.47 and 0.28 in the cold season (p < 0.05) and 0.52, 0.45 and 0.35 in the warm season (p < 0.001), respectively. Energy and fat intake, sex, age, BMI and educational level adjusted Pearson correlation coefficient for FV with dietary reference method in the cold and warm seasons were 0.62 and 0.60, respectively (p < 0.001). Intraclass correlation for reproducibility of FFQ in FV was 0.65 (p<0.001). CONCLUSIONS: The designed FFQ had a good criterion validity and reproducibility for assessment of FV intake. Thus, it can serve as a valid tool in epidemiological studies to assess fruit and vegetable intake. PMID:22973322

Advancing Methods for Estimating Soil Nitrous Oxide Emissions by Incorporating Freeze-Thaw Cycles into a Tier 3 Model-Based Assessment

NASA Astrophysics Data System (ADS)

Ogle, S. M.; DelGrosso, S.; Parton, W. J.

2017-12-01

Soil nitrous oxide emissions from agricultural management are a key source of greenhouse gas emissions in many countries due to the widespread use of nitrogen fertilizers, manure amendments from livestock production, planting legumes and other practices that affect N dynamics in soils. In the United States, soil nitrous oxide emissions have ranged from 250 to 280 Tg CO2 equivalent from 1990 to 2015, with uncertainties around 20-30 percent. A Tier 3 method has been used to estimate the emissions with the DayCent ecosystem model. While the Tier 3 approach is considerably more accurate than IPCC Tier 1 methods, there is still the possibility of biases in emission estimates if there are processes and drivers that are not represented in the modeling framework. Furthermore, a key principle of IPCC guidance is that inventory compilers estimate emissions as accurately as possible. Freeze-thaw cycles and associated hot moments of nitrous oxide emissions are one of key drivers influencing emissions in colder climates, such as the cold temperate climates of the upper Midwest and New England regions of the United States. Freeze-thaw activity interacts with management practices that are increasing N availability in the plant-soil system, leading to greater nitrous oxide emissions during transition periods from winter to spring. Given the importance of this driver, the DayCent model has been revised to incorproate freeze-thaw cycles, and the results suggests that including this driver can significantly modify the emissions estimates in cold temperate climate regions. Consequently, future methodological development to improve estimation of nitrous oxide emissions from soils would benefit from incorporating freeze-thaw cycles into the modeling framework for national territories with a cold climate.

Effects of urban density on carbon dioxide exchanges: Observations of dense urban, suburban and woodland areas of southern England.

PubMed

Ward, H C; Kotthaus, S; Grimmond, C S B; Bjorkegren, A; Wilkinson, M; Morrison, W T J; Evans, J G; Morison, J I L; Iamarino, M

2015-03-01

Anthropogenic and biogenic controls on the surface-atmosphere exchange of CO2 are explored for three different environments. Similarities are seen between suburban and woodland sites during summer, when photosynthesis and respiration determine the diurnal pattern of the CO2 flux. In winter, emissions from human activities dominate urban and suburban fluxes; building emissions increase during cold weather, while traffic is a major component of CO2 emissions all year round. Observed CO2 fluxes reflect diurnal traffic patterns (busy throughout the day (urban); rush-hour peaks (suburban)) and vary between working days and non-working days, except at the woodland site. Suburban vegetation offsets some anthropogenic emissions, but 24-h CO2 fluxes are usually positive even during summer. Observations are compared to estimated emissions from simple models and inventories. Annual CO2 exchanges are significantly different between sites, demonstrating the impacts of increasing urban density (and decreasing vegetation fraction) on the CO2 flux to the atmosphere. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Warmer winters modulate life history and energy storage but do not affect sensitivity to a widespread pesticide in an aquatic insect.

PubMed

Arambourou, Hélène; Stoks, Robby

2015-10-01

Despite the increased attention for the effects of pesticides under global warming no studies tested how winter warming affects subsequent sensitivity to pesticides. Winter warming is expected to cause delayed negative effects when it increases metabolic rates and thereby depletes energy reserves. Using a common-garden experiment, we investigated the combined effect of a 4 °C increase in winter temperature and subsequent exposure to chlorpyrifos in the aquatic larvae of replicated low- and high-latitude European populations of the damselfly Ischnura elegans. The warmer winter (8 °C) resulted in a higher winter survival and higher growth rates compared to the cold winter (4 °C) commonly experienced by European high-latitude populations. Low-latitude populations were better at coping with the warmer winter, indicating thermal adaptation to the local winter temperatures. Subsequent chlorpyrifos exposure at 20 °C induced strong negative effects on survival, growth rate, lipid content and acetylcholinesterase activity while phenoloxidase activity increased. These pesticide effects were not affected by winter warming. Our results suggest that for species where winter warming has positive effects on life history, no delayed effects on the sensitivity to subsequent pesticide exposure should be expected. Copyright © 2015 Elsevier B.V. All rights reserved.

Shoot winter injury and nut cold tolerance: Possible limitations for American chestnut restoration in cold environments? In: Sniezko, Richard A.; Yanchuk, Alvin D.; Kliejunas, John T.; Palmieri, Katharine M.; Alexander, Janice M.; Frankel, Susan J., tech

Treesearch

Thomas M. Saielli; Paul G. Schaberg; Gary J. Hawley; Joshua M. Halman; Kendra M. Gurney

2012-01-01

Approximately 100 years ago, American chestnut (Castanea dentata (Marsh.) Borkh.) was rapidly removed as an overstory tree by the fungal pathogen Cryphonectria parasitica (the causal agent of chestnut blight). Currently, the most effective method of restoration involves the hybridization of American chestnut with the...

Installation Restoration Program Records Search for 158 Tactical Fighter Group, Vermont Air National Guard, Burlington International Airport.

DTIC Science & Technology

1983-09-01

cold winters. Coldest temperatures ir. winter months are caused by high pressure systems which move rapidly dohn from central Canada cr Hudson Eay... dolomitic marble; or sand (30 to 60 feet), Glacial till (30 to 50 feet), and bedrock. The materials occurring above the bedrock in the vicinity of the...Trenton Group Iberville formation Noncalcareous black shale interbedded with 1000 dolomite . Stony point formation Predominantly calcareous black shale

Belaya smert: the white death.

PubMed

Rodway, George W

2012-09-01

In the late autumn of 1939, shortly after Second World War had commenced, the Soviet Union invaded Finland. This act of military aggression, henceforth known to history as the Winter War, was ostensibly carried out to secure a buffer state and better protect major urban areas such as St. Petersburg (then known as Leningrad). The Red Army's attack through the forests of northern Finland was a poorly calculated operation-in the little more than 3 months that the conflict lasted, the Soviets suffered extensive losses. The hit-and-run tactics of the small, winter-savvy Finnish Army resulted in a not significant number of Red Army casualties. But from the Soviet perspective, the Finnish soldiers were merely an annoyance compared with the real enemy--the environment. Cold injury reached epidemic proportions in the Red Army during this short conflict, apparently caused in large part by ignorance of environmental realities by the Soviet high command. Paradoxically, the Soviets arguably possessed the most extensive and sophisticated body of knowledge about cold injury prevention and treatment on earth by the late 1930s. There were significant lessons learned by the Soviets during the Winter War, however. When Germany invaded the Soviet Union in 1941, the Red Army very successfully applied these lessons during 4 years of vicious winter battles on the Eastern Front. Copyright © 2012 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Wintertime ozone and nitrogen oxide photochemistry and nighttime chemistry in a Western oil and gas basin

NASA Astrophysics Data System (ADS)

Brown, S. S.; Edwards, P. M.; Patel, S.; Dube, W. P.; Williams, E. J.; Roberts, J. M.; McLaren, R.; Kercher, J. P.; Gilman, J. B.; Lerner, B. M.; Warneke, C.; Geiger, F.; De Gouw, J. A.; Tsai, C.; Stutz, J.; Young, C. J.; Washenfelder, R. A.; Parrish, D. D.

2012-12-01

Oil and gas development in mountain basins of the Western United States has led to frequent exceedences of National Ambient Air Quality Standards for ozone during the winter season. The Uintah Basin Winter Ozone Study took place during February and March 2012 in northeast Utah with the goal of providing detailed chemical and meteorological data to understand this phenomenon. Although snow and cold pool stagnation conditions that lead to winter ozone buildup were not encountered during the study period, the detailed measurements did provide a unique data set to understand the chemistry of key air pollutants in a desert environment during winter. This presentation will examine both the photochemistry and the nighttime chemistry of nitrogen oxides, ozone and VOCs, with the goal of understanding the observed photochemistry and its relationship to nighttime chemistry through a set of box models. The photochemical box model is based on the master chemical mechanism (MCM), a detailed model for VOC degradation and ozone production. The presentation will examine the sensitivity of ozone photochemistry to different parameters, including pollutant concentrations likely to be characteristic of cold pool conditions, and the strength of radical sources derived from heterogeneous chemical reactions. The goal of the analysis will be to identify the factors most likely to be responsible for the higher ozone events that have been observed during colder years with less detailed chemical measurements.

A closer look at the relationships between meridional mass circulation pulses in the stratosphere and cold air outbreak patterns in northern hemispheric winter

NASA Astrophysics Data System (ADS)

Yu, Yueyue; Cai, Ming; Ren, Rongcai; Rao, Jian

2018-01-01

The relationship between continental-scale cold air outbreaks (CAOs) in the mid-latitudes and pulse signals in the stratospheric mass circulation in Northern Hemisphere winter (December-February) is investigated using ERA-Interim data for the 32 winters from 1979 to 2011. Pulse signals in the stratospheric mass circulation include "PULSE_TOT", "PULSE_W1", and "PULSE_W2" events, defined as a period of stronger meridional mass transport into the polar stratosphere by total flow, wavenumber-1, and wavenumber-2, respectively. Each type of PULSE event occurs on average 4-6 times per winter. A robust relationship is found between two dominant patterns of winter CAOs and PULSE_W1 and PULSE_W2 events. Cold temperature anomalies tend to occur over Eurasia with the other continent anomalously warm during the 2 weeks before the peak dates of PULSE_W1 events, while the opposite temperature anomaly pattern can be found after the peak dates; and during the 1-2 weeks centered on the peak dates of PULSE_W2 events, a higher probability of occurrence of CAOs is found over both continents. These relationships become more robust for PULSE_W1 and PULSE_W2 events of larger peak intensity. PULSE_TOT events are classified into five types, which have a distinct coupling relationship with PULSE_W1 and PULSE_W2 events. The specific pattern of CAOs associated with each type of PULSE_TOT event is found to be a combination of the CAO patterns associated with PULSE_W1 and PULSE_W2 events. The percentage of PULSE_TOT events belonging to the types that are dominated by PULSE_W2 events increases with the peak intensity of PULSE_TOT events. Accordingly, the related CAO pattern is close to that associated with PULSE_W1 for PULSE_TOT events with small-to-medium intensity, but tends to resemble that associated with PULSE_W2 events as the peak intensity of PULSE_TOT events increases.

Improved antioxidative protection in winter swimmers.

PubMed

Siems, W G; Brenke, R; Sommerburg, O; Grune, T

1999-04-01

Adaptation to oxidative stress is an improved ability to resist the damaging effects of reactive oxygen species, resulting from pre-exposure to a lower dose. Changes in uric acid and glutathione levels during ice-bathing suggest that the intensive voluntary short-term cold exposure of winter swimming produces oxidative stress. We investigated whether the repeated oxidative stress in winter swimmers results in improved antioxidative adaptation. We obtained venous blood samples from winter swimmers and determined important components of the antioxidative defense system in the erythrocytes or blood plasma: reduced and oxidized glutathione (GSH and GSSG), and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat). The control group consisted of healthy people who had never participated in winter swimming. The baseline concentration of GSH and the activities of erythrocytic SOD and Cat, were higher in winter swimmers. We interpret this as an adaptative response to repeated oxidative stress, and postulate it as a new basic molecular mechanism of increased tolerance to environmental stress.

Comparing Model Ozone Loss during the SOLVE and SOLVE-2 Winters

NASA Technical Reports Server (NTRS)

Drdla, K.

2003-01-01

Model simulations have been used to analyze the factors influencing ozone loss during the 1999-2000 and 2002-2003 js. For both winters, the evolution of the Arctic vortex from November to April has been simulated using a trajectory-based microphysical and photochemical model. Extensive PSC formation and strong ozone depletion are evident in both winters. However, the ozone loss begins earlier in the 2002-2003 winter, with significant ozone depletion by early January. Analysis of the model results shows that during December 2002 not only cold temperatures but also the vortex structure was critical, allowing PSC-processed air parcels to experience significant solar exposure. The resultant ozone loss can be differentiated from ozone loss that occurs in the springtime, in particular because of the continued exposure to PSCs. For example, chlorine reactivation by the PSCs causes ozone loss to be insensitive to denitrification. Therefore, diagnosing the extent of ozone loss early in the winter is critical In understanding the overall winter-long ozone depletion.

Seed dormancy and germination of Halophila ovalis mediated by simulated seasonal temperature changes

NASA Astrophysics Data System (ADS)

Statton, John; Sellers, Robert; Dixon, Kingsley W.; Kilminster, Kieryn; Merritt, David J.; Kendrick, Gary A.

2017-11-01

The seagrass, Halophila ovalis plays an important ecological and sediment stability role in estuarine systems in Australia with the species in decline in many sites. Halophila ovalis is a facultative annual, relying mainly on recruitment from the sediment seed bank for the annual regeneration of meadows. Despite this, there is little understanding of seed dormancy releasing mechanisms and germination cues. Using H. ovalis seed from the warm temperate Swan River Estuary in Western Australia, the germination ecology of H. ovalis was investigated by simulating the natural seasonal variation in water temperatures. The proportion of germinating seeds was found to be significantly different among temperature treatments (p < 0.001). The treatment with the longest period of cold exposure at 15 °C followed by an increase in temperature to 20-25 °C (i.e. cold stratification) had the highest final mean germination of 32% and the fastest germination rate. Seeds exposed to constant mean winter temperatures of 15 °C had the slowest germination rate with less than two seeds germinating over 118 days. Thus temperature is a key germination cue for H. ovalis seeds and these data infer that cold stratification is an important dormancy releasing mechanism. This finding has implications for recruitment in facultative annual species like H. ovalis under global warming since the trend for increasing water temperatures in the region may limit seed-based recruitment in the future.

The winter-red-leaf syndrome in Pistacia lentiscus: evidence that the anthocyanic phenotype suffers from nitrogen deficiency, low carboxylation efficiency and high risk of photoinhibition.

PubMed

Nikiforou, Constantinos; Nikolopoulos, Dimosthenis; Manetas, Yiannis

2011-12-15

Recent evidence indicates that winter-red leaf phenotypes in the mastic tree (Pistacia lentiscus) are more vulnerable to chronic photoinhibition during the cold season relative to winter-green phenotypes occurring in the same high light environment. This was judged by limitations in the maximum quantum yield of photosystem II (PSII), found in previous studies. In this investigation, we asked whether corresponding limitations in leaf gas exchange and carboxylation reactions could also be manifested. During the cold ("red") season, net CO₂ assimilation rates (A) and stomatal conductances (g(s)) in the red phenotype were considerably lower than in the green phenotype, while leaf internal CO₂ concentration (Ci) was higher. The differences were abolished in the "green" period of the year, the dry summer included. Analysis of A versus Ci curves indicated that CO₂ assimilation during winter in the red phenotype was limited by Rubisco content and/or activity rather than stomatal conductance. Leaf nitrogen levels in the red phenotype were considerably lower during the red-leaf period. Consequently, we suggest that the inherently low leaf nitrogen levels are linked to the low net photosynthetic rates of the red plants through a decrease in Rubisco content. Accordingly, the reduced capacity of the carboxylation reactions to act as photosynthetic electron sinks may explain the corresponding loss of PSII photon trapping efficiency, which cannot be fully alleviated by the screening effect of the accumulated anthocyanins. Copyright © 2011 Elsevier GmbH. All rights reserved.

The role of the winter residual circulation in the summer mesopause regions in WACCM

NASA Astrophysics Data System (ADS)

Sanne Kuilman, Maartje; Karlsson, Bodil

2018-03-01

High winter planetary wave activity warms the summer polar mesopause via a link between the two hemispheres. Complex wave-mean-flow interactions take place on a global scale, involving sharpening and weakening of the summer zonal flow. Changes in the wind shear occasionally generate flow instabilities. Additionally, an altering zonal wind modifies the breaking of vertically propagating gravity waves. A crucial component for changes in the summer zonal flow is the equatorial temperature, as it modifies latitudinal gradients. Since several mechanisms drive variability in the summer zonal flow, it can be hard to distinguish which one is dominant. In the mechanism coined interhemispheric coupling, the mesospheric zonal flow is suggested to be a key player for how the summer polar mesosphere responds to planetary wave activity in the winter hemisphere. We here use the Whole Atmosphere Community Climate Model (WACCM) to investigate the role of the summer stratosphere in shaping the conditions of the summer polar mesosphere. Using composite analyses, we show that in the absence of an anomalous summer mesospheric temperature gradient between the equator and the polar region, weak planetary wave forcing in the winter would lead to a warming of the summer mesosphere region instead of a cooling, and vice versa. This is opposing the temperature signal of the interhemispheric coupling that takes place in the mesosphere, in which a cold and calm winter stratosphere goes together with a cold summer mesopause. We hereby strengthen the evidence that the variability in the summer mesopause region is mainly driven by changes in the summer mesosphere rather than in the summer stratosphere.

Changes in chemical components in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), in relation to the development of its cold hardiness.

PubMed

Matsukura, Keiichiro; Tsumuki, Hisaaki; Izumi, Yohei; Wada, Takashi

2008-04-01

The apple snail, Pomacea canaliculata, is an invasive freshwater snail. It increases its cold hardiness before winter. However, the physiological mechanism of cold hardiness in molluscs is poorly understood, especially in freshwater molluscs. In this study, we examined the changes in low molecular weight compounds, glycogen and lipids, in the body of P. canaliculata in association with the development of cold hardiness. When snails without cold hardiness were experimentally cold-acclimated, the amount of glycerol, glutamine, and carnosine increased, while glycogen and phenylalanine decreased. Overwintering cold-tolerant snails collected from a drained paddy field in November also showed increased glycerol in their bodies with decreasing glycogen concentration, compared to summer snails collected from a submerged field. Water content also decreased during the cold acclimation, although the water loss was minimal. These results indicate that the freshwater snail, P. canaliculata enhances cold hardiness by accumulation of some kinds of low molecular weight compounds in its body as some insects do. However, the actual function of each low molecular compound is still unknown.

Changes in ABA and gene expression in cold-acclimated sugar maple.

PubMed

Bertrand, A; Robitaille, G; Castonguay, Y; Nadeau, P; Boutin, R

1997-01-01

To determine if cold acclimation of sugar maple (Acer saccharum Marsh.) is associated with specific changes in gene expression under natural hardening conditions, we compared bud and root translatable mRNAs of potted maple seedlings after cold acclimation under natural conditions and following spring dehardening. Cold-hardened roots and buds were sampled in January when tissues reached their maximum hardiness. Freezing tolerance, expressed as the lethal temperature for 50% of the tissues (LT(50)), was estimated at -17 degrees C for roots, and at lower than -36 degrees C for buds. Approximately ten transcripts were specifically synthesized in cold-acclimated buds, or were more abundant in cold-acclimated buds than in unhardened buds. Cold hardening was also associated with changes in translation. At least five translation products were more abundant in cold-acclimated buds and roots compared with unhardened tissues. Abscisic acid (ABA) concentration increased approximately tenfold in the xylem sap following winter acclimation, and the maximum concentration was reached just before maximal acclimation. We discuss the potential involvement of ABA in the observed modification of gene expression during cold hardening.

Conditional cold avoidance drives between-population variation in germination behaviour in Calluna vulgaris.

PubMed

Spindelböck, Joachim P; Cook, Zoë; Daws, Matthew I; Heegaard, Einar; Måren, Inger E; Vandvik, Vigdis

2013-09-01

Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season. Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range. Incubation treatments varied from 10 to 25 °C, and germination performance across populations was analysed in relation to temperature conditions at the seed collection locations. Seeds from all populations germinated rapidly and to high final percentages under the warmer incubation temperatures. Under low incubation temperatures, cold-climate populations had significantly lower germination rates and percentages than warm-climate populations. While germination rates and percentages also increased with seed mass, seed mass did not vary along the climatic gradients, and therefore did not explain the variation in germination responses. Variation in germination responses among Calluna populations was consistent with increased temperature requirements for germination towards colder climates, indicating a cold-avoidance germination strategy conditional on the temperature at the seeds' origin. Along a gradient of increasing temperatures this suggests a shift in selection pressures on germination from climatic adversity (i.e. low temperatures and potential frost risk in early or late season) to competitive performance and better exploitation of the entire growing season.

Conditional cold avoidance drives between-population variation in germination behaviour in Calluna vulgaris

PubMed Central

Spindelböck, Joachim P.; Cook, Zoë; Daws, Matthew I.; Heegaard, Einar; Måren, Inger E.; Vandvik, Vigdis

2013-01-01

Background and Aims Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season. Methods Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range. Incubation treatments varied from 10 to 25 °C, and germination performance across populations was analysed in relation to temperature conditions at the seed collection locations. Key Results Seeds from all populations germinated rapidly and to high final percentages under the warmer incubation temperatures. Under low incubation temperatures, cold-climate populations had significantly lower germination rates and percentages than warm-climate populations. While germination rates and percentages also increased with seed mass, seed mass did not vary along the climatic gradients, and therefore did not explain the variation in germination responses. Conclusions Variation in germination responses among Calluna populations was consistent with increased temperature requirements for germination towards colder climates, indicating a cold-avoidance germination strategy conditional on the temperature at the seeds' origin. Along a gradient of increasing temperatures this suggests a shift in selection pressures on germination from climatic adversity (i.e. low temperatures and potential frost risk in early or late season) to competitive performance and better exploitation of the entire growing season. PMID:23884396

The effects of climate change on heating energy consumption of office buildings in different climate zones in China

NASA Astrophysics Data System (ADS)

Meng, Fanchao; Li, Mingcai; Cao, Jingfu; Li, Ji; Xiong, Mingming; Feng, Xiaomei; Ren, Guoyu

2017-06-01

Climate plays an important role in heating energy consumption owing to the direct relationship between space heating and changes in meteorological conditions. To quantify the impact, the Transient System Simulation Program software was used to simulate the heating loads of office buildings in Harbin, Tianjin, and Shanghai, representing three major climate zones (i.e., severe cold, cold, and hot summer and cold winter climate zones) in China during 1961-2010. Stepwise multiple linear regression was performed to determine the key climatic parameters influencing heating energy consumption. The results showed that dry bulb temperature (DBT) is the dominant climatic parameter affecting building heating loads in all three climate zones across China during the heating period at daily, monthly, and yearly scales (R 2 ≥ 0.86). With the continuous warming climate in winter over the past 50 years, heating loads decreased by 14.2, 7.2, and 7.1 W/m2 in Harbin, Tianjin, and Shanghai, respectively, indicating that the decreasing rate is more apparent in severe cold climate zone. When the DBT increases by 1 °C, the heating loads decrease by 253.1 W/m2 in Harbin, 177.2 W/m2 in Tianjin, and 126.4 W/m2 in Shanghai. These results suggest that the heating energy consumption can be well predicted by the regression models at different temporal scales in different climate conditions owing to the high determination coefficients. In addition, a greater decrease in heating energy consumption in northern severe cold and cold climate zones may efficiently promote the energy saving in these areas with high energy consumption for heating. Particularly, the likely future increase in temperatures should be considered in improving building energy efficiency.

Ozone photochemistry in an oil and natural gas extraction region during winter: simulations of a snow-free season in the Uintah Basin, Utah

NASA Astrophysics Data System (ADS)

Edwards, P. M.; Young, C. J.; Aikin, K.; deGouw, J. A.; Dubé, W. P.; Geiger, F.; Gilman, J. B.; Helmig, D.; Holloway, J. S.; Kercher, J.; Lerner, B.; Martin, R.; McLaren, R.; Parrish, D. D.; Peischl, J.; Roberts, J. M.; Ryerson, T. B.; Thornton, J.; Warneke, C.; Williams, E. J.; Brown, S. S.

2013-03-01

The Uintah Basin in northeastern Utah, a region of intense oil and gas extraction, experienced ozone (O3) concentrations above levels harmful to human health for multiple days during the winters of 2009-2010 and 2010-2011. These wintertime O3 pollution episodes occur during cold, stable periods when the ground is snowcovered, and have been linked to emissions from the oil and gas extraction process. The Uintah Basin Winter Ozone Study (UBWOS) was a field intensive in early 2012, whose goal was to address current uncertainties in the chemical and physical processes that drive wintertime O3 production in regions of oil and gas development. Although elevated O3 concentrations were not observed during the winter of 2011-2012, the comprehensive set of observations tests of our understanding of O3 photochemistry in this unusual emissions environment. A box model, constrained to the observations and using the explicit Master Chemical Mechanism (MCM) V3.2 chemistry scheme, has been used to investigate the sensitivities of O3 production during UBWOS 2012. Simulations identify the O3 production photochemistry to be highly radical limited. Production of OH from O3 photolysis (through reaction of O(1D) with water vapor) contributed only 170 pptv day-1, 8% of the total primary radical source on average. Other radical sources, including the photolysis of formaldehyde (HCHO, 52%), nitrous acid (HONO, 26%), and nitryl chloride (ClNO2, 13%) were larger. O3 production was also found to be highly sensitive to aromatic volatile organic compound (VOC) concentrations, due to radical amplification reactions in the oxidation scheme of these species. Radical production was shown to be small in comparison to the emissions of nitrogen oxides (NOx), such that NOx acted as the primary radical sink. Consequently, the system was highly VOC sensitive, despite the much larger mixing ratio of total non-methane hydrocarbons (230 ppbv (2080 ppbC), 6 week average) relative to NOx (5.6 ppbv average). However, the importance of radical sources which are themselves derived from NOx emissions and chemistry, such as ClNO2 and HONO, make the response of the system to changes in NOx emissions uncertain. These box model simulations provide useful insight into the chemistry controlling winter O3 production in regions of oil and gas extraction.

Climate change and ecosystem disruption: the health impacts of the North American Rocky Mountain pine beetle infestation.

PubMed

Embrey, Sally; Remais, Justin V; Hess, Jeremy

2012-05-01

In the United States and Canada, pine forest ecosystems are being dramatically affected by an unprecedented pine beetle infestation attributed to climate change. Both decreased frequency of extremely cold days and warmer winter temperature averages have led to an enphytotic devastating millions of acres of pine forest. The associated ecosystem disruption has the potential to cause significant health impacts from a range of exposures, including increased runoff and water turbidity, forest fires, and loss of ecosystem services. We review direct and indirect health impacts and possible prevention strategies. The pine beetle infestation highlights the need for public health to adopt an ecological, systems-oriented view to anticipate the full range of potential health impacts from climate change and facilitate effective planned adaptation.

Climate Change and Ecosystem Disruption: The Health Impacts of the North American Rocky Mountain Pine Beetle Infestation

PubMed Central

Remais, Justin V.; Hess, Jeremy

2012-01-01

In the United States and Canada, pine forest ecosystems are being dramatically affected by an unprecedented pine beetle infestation attributed to climate change. Both decreased frequency of extremely cold days and warmer winter temperature averages have led to an enphytotic devastating millions of acres of pine forest. The associated ecosystem disruption has the potential to cause significant health impacts from a range of exposures, including increased runoff and water turbidity, forest fires, and loss of ecosystem services. We review direct and indirect health impacts and possible prevention strategies. The pine beetle infestation highlights the need for public health to adopt an ecological, systems-oriented view to anticipate the full range of potential health impacts from climate change and facilitate effective planned adaptation. PMID:22420788

Cold hardiness in relation to trace metal stress in the freeze-avoiding beetle Tenebrio molitor.

PubMed

Pedersen, Sindre A; Kristiansen, Erlend; Hansen, Bjørn H; Andersen, Rolf A; Zachariassen, Karl E

2006-08-01

The antifreeze proteins (AFPs) are a family of proteins characterised by their ability to inhibit the growth of ice. These proteins have evolved as a protection against lethal freezing in freeze avoiding species. Metal stress has been shown to reduce the cold hardening in invertebrates, but no study has investigated how this type of stress affects the production of AFPs. This study demonstrates that exposure to cadmium (Cd), copper (Cu) and zinc (Zn) reduces the normal developmental increase in AFP levels in Tenebrio molitor larvae reared under summer conditions. Exposure to winter conditions, however stimulated the production of AFPs in the metal exposed larvae, and raised the concentrations of AFPs to normal winter levels. The reduced level of AFPs in metal-stressed animals acclimated to summer conditions seems to arise from alterations in the normal gene expression of AFPs. The results indicate that metal exposure may cause freeze avoiding insects to become more susceptible to lethal freezing, as they enter the winter with lowered levels of AFPs. Such an effect cannot be revealed by ordinary toxicological tests, but may nevertheless be of considerable ecological importance.

Carbon, water, and energy fluxes in a semiarid cold desert grassland during and following multiyear drought

USGS Publications Warehouse

Bowling, David R.; Bethers-Marchetti, S.; Lunch, C.K.; Grote, E.E.; Belnap, J.

2010-01-01

The net exchanges of carbon dioxide, water vapor, and energy were examined in a perennial Colorado Plateau grassland for 5 years. The study began within a multiyear drought and continued as the drought ended. The grassland is located near the northern boundary of the influence of the North American monsoon, a major climatic feature bringing summer rain. Following rain, evapotranspiration peaked above 8 mm d-1 but was usually much smaller (2-4 mm d-1). Net productivity of the grassland was low compared to other ecosystems, with peak hourly net CO2 uptake in the spring of 4 (mu or u)mol m-2 s-1 and springtime carbon gain in the range of 42 + or - 11 g C m-2 (based on fluxes) to 72 + or - 55 g C m-2 (based on carbon stocks; annual carbon gain was not quantified). Drought decreased gross ecosystem productivity (GEP) and total ecosystem respiration, with a much larger GEP decrease. Monsoon rains led to respiratory pulses, lasting a few days at most, and only rarely resulted in net CO2 gain, despite the fact that C4 grasses dominated plant cover. Minor CO2 uptake was observed in fall following rain. Spring CO2 uptake was regulated by deep soil moisture, which depended on precipitation in the prior fall and winter. The lack of CO2 uptake during the monsoon and the dependence of GEP on deep soil moisture are in contrast with arid grasslands of the warm deserts. Cold desert grasslands are most likely to be impacted by future changes in winter and not summer precipitation.

Climate and respiratory disease in Auckland, New Zealand.

PubMed

Gosai, Ashmita; Salinger, James; Dirks, Kim

2009-12-01

Increases in the incidence of diseases are often observed during the cold winter months, particularly in cities in temperate climates. The study aim is to describe daily, monthly and seasonal trends in respiratory hospital admissions with climate in Auckland, New Zealand. Daily hospital admissions for total respiratory infections or inflammations (RII), total bronchitis and asthma (BA), and total whooping cough and acute bronchitis (TWCAB) for various age groups and ethnicities were obtained for the Auckland Region and compared with climate parameters on daily, monthly and seasonal time scales. Seasonal and monthly relationships with minimum temperature were very strong (p<0.001) for RII over all age groups, for BA in the older age groups (14-64, 65+) and for TWCAB in the <1 year old age group. European, NZ Māori and Pacific Islanders all showed increases in admissions as temperatures decreased. Pacific Islanders were particularly susceptible to RII. There was a lag in admissions of three to seven days after a temperature event. Results show that increases in respiratory admissions are strongly linked to minimum temperatures during winter, typical of cities with temperate climates and poorly-insulated houses. There are implications for hospital bed and staffing planning in Auckland hospitals.

Local health and social care responses to implementing the national cold weather plan.

PubMed

Heffernan, C; Jones, L; Ritchie, B; Erens, B; Chalabi, Zaid; Mays, N

2017-09-18

The Cold Weather Plan (CWP) for England was launched by the Department of Health in 2011 to prevent avoidable harm to health by cold weather by enabling individuals to prepare and respond appropriately. This study sought the views of local decision makers involved in the implementation of the CWP in the winter of 2012/13 to establish the effects of the CWP on local planning. It was part of a multi-component independent evaluation of the CWP. Ten LA areas were purposively sampled which varied in level of deprivation and urbanism. Fifty-two semi-structured interviews were held with health and social care managers involved in local planning between November 2012 and May 2013. Thematic analysis revealed that the CWP was considered a useful framework to formalize working arrangements between agencies though local leadership varied across localities. There were difficulties in engaging general practitioners, differences in defining vulnerable individuals and a lack of performance monitoring mechanisms. The CWP was welcomed by local health and social care managers, and improved proactive winter preparedness. Areas for improvement include better integration with general practice, and targeting resources at socially isolated individuals in cold homes with specific interventions aimed at reducing social isolation and building community resilience. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Green Supercomputing at Argonne

ScienceCinema

Pete Beckman

2017-12-09

Pete Beckman, head of Argonne's Leadership Computing Facility (ALCF) talks about Argonne National Laboratory's green supercomputing—everything from designing algorithms to use fewer kilowatts per operation to using cold Chicago winter air to cool the machine more efficiently.

Synoptic aspects of Antarctic mesocyclones

NASA Astrophysics Data System (ADS)

Carleton, Andrew M.; Fitch, Mark

1993-07-01

The characteristic regimes (formation and dissipation areas, tracks) and synoptic environments of cold air mesocyclones over Antarctic and Subantarctic latitudes are determined for the contrasting winters (June, July, and August) of 1988 and 1989. Defense Meteorological Satellite Program (DMSP) thermal infrared (IR) imagery is used in conjunction with southern hemisphere pressure/height analyses. Outbreaks of mesocyclones ("active periods") are frequent in the Ross Sea sector in 1988. They are associated most often with areas of maximum horizontal gradient of the 1000- to 500-mbar thickness. Over higher latitudes of the Southeast Pacific in 1989, mesocyclones develop in association with a "cold pool" that migrates equatorward. The between-winter differences in mesocyclone frequencies are examined for associations with sea ice conditions and the continental katabatic winds using correlation and "superposed epoch" analysis of temperature data from selected automatic weather stations (AWSs). The results support a katabatic wind-sea ice extent-mesocyclone link for key sectors of the Antarctic.

The Cold Hardiness of Phrynocephalus erythrurus, the Lizard Living at Highest Altitude in the World.

PubMed

Li, X T; Wang, Y; Lu, S S; Li, M; Men, S K; Bai, Y C; Tang, X L; Chen, Q

Phrynocephalus erythrurus living at Qinghai-Tibet Plateau, is believed to be the highest lizard in the world, but we know little about how these lizards cope with very low temperatures in winter. The aim of this study was to find the difference of the lizards before and after cold acclimatization. In this study the limit of supercooling and inoculative freezing, the concentration of four organic osmolytes, and the activity of lactate dehydrogenase in the plasma were measured in samples shortly after capture and in other samples after 7~8 weeks of acclimatization at 2~4 degree C. Animals acquired an ability to undergo deeper supercooling and inoculative freezing through the course of acclimatization. We find no regular changes of the four organic osmolytes after the acclimatization. We think that this species of lizard is partly freeze-tolerant and conclude that it uses supercooling to survive in winter.

Seasonal reversal at Miryang Eoreumgol (Ice Valley), Korea: observation and monitoring

NASA Astrophysics Data System (ADS)

Byun, Hi-Ryong; Tanaka, Hiroshi L.; Choi, Pom-Yong; Kim, Do-Woo

2011-12-01

We investigate an anomalous phenomenon evident in the Miryang Eoreumgol (Ice Valley), Korea: The wind and water are cold during summer and warm during winter, and ice formation does not occur in winter but in summer. We have initiated observations and investigations into the origin of heat sources particularly with regard to the mechanism of ice formation in summer. Previous theories, e.g., concerning underground gravity currents, water evaporation, diurnal and seasonal respirations of the talus, effects of ground heat, radiation and topography, etc., are considered. After a calculation of heat sources, we propose two new concepts—a repetitious heat separation mechanism and a positive feedback mechanism of cold air generation—to demonstrate that the heat mechanism of the seasonal reversal of the ice valley may be controlled by the use of the phase change between ice and water vapor with only a small amount of additional unknown energy.

IOCCG Report Number 16, 2015 Ocean Colour Remote Sensing in Polar Seas . Chapter 2; The Polar Environment: Sun, Clouds, and Ice

NASA Technical Reports Server (NTRS)

Comiso, Josefino C.; Perovich, Don; Stamnes, Knut; Stuart, Venetia (Editor)

2015-01-01

The polar regions are places of extremes. There are months when the regions are enveloped in unending darkness, and months when they are in continuous daylight. During the daylight months the sun is low on the horizon and often obscured by clouds. In the dark winter months temperatures are brutally cold, and high winds and blowing snow are common. Even in summer, temperatures seldom rise above 0degC. The cold winter temperatures cause the ocean to freeze, forming sea ice. This sea ice cover acts as a barrier limiting the transfer of heat, moisture, and momentum between the atmosphere and the ocean. It also greatly complicates the optical signature of the surface. Taken together, these factors make the polar regions a highly challenging environment for optical remote sensing of the ocean.

The impact of changing the land surface scheme in ACCESS(v1.0/1.1) on the surface climatology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kowalczyk, Eva A.; Stevens, Lauren E.; Law, Rachel M.

The Community Atmosphere Biosphere Land Exchange (CABLE) model has been coupled to the UK Met Office Unified Model (UM) within the existing framework of the Australian Community Climate and Earth System Simulator (ACCESS), replacing the Met Office Surface Exchange Scheme (MOSES). Here we investigate how features of the CABLE model impact on present-day surface climate using ACCESS atmosphere-only simulations. The main differences attributed to CABLE include a warmer winter and a cooler summer in the Northern Hemisphere (NH), earlier NH spring runoff from snowmelt, and smaller seasonal and diurnal temperature ranges. The cooler NH summer temperatures in canopy-covered regions aremore » more consistent with observations and are attributed to two factors. Firstly, CABLE accounts for aerodynamic and radiative interactions between the canopy and the ground below; this placement of the canopy above the ground eliminates the need for a separate bare ground tile in canopy-covered areas. Secondly, CABLE simulates larger evapotranspiration fluxes and a slightly larger daytime cloud cover fraction. Warmer NH winter temperatures result from the parameterization of cold climate processes in CABLE in snow-covered areas. In particular, prognostic snow density increases through the winter and lowers the diurnally resolved snow albedo; variable snow thermal conductivity prevents early winter heat loss but allows more heat to enter the ground as the snow season progresses; liquid precipitation freezing within the snowpack delays the building of the snowpack in autumn and accelerates snow melting in spring. Altogether we find that the ACCESS simulation of surface air temperature benefits from the specific representation of the turbulent transport within and just above the canopy in the roughness sublayer as well as the more complex snow scheme in CABLE relative to MOSES.« less

The impact of changing the land surface scheme in ACCESS(v1.0/1.1) on the surface climatology

DOE PAGES

Kowalczyk, Eva A.; Stevens, Lauren E.; Law, Rachel M.; ...

2016-08-23

The Community Atmosphere Biosphere Land Exchange (CABLE) model has been coupled to the UK Met Office Unified Model (UM) within the existing framework of the Australian Community Climate and Earth System Simulator (ACCESS), replacing the Met Office Surface Exchange Scheme (MOSES). Here we investigate how features of the CABLE model impact on present-day surface climate using ACCESS atmosphere-only simulations. The main differences attributed to CABLE include a warmer winter and a cooler summer in the Northern Hemisphere (NH), earlier NH spring runoff from snowmelt, and smaller seasonal and diurnal temperature ranges. The cooler NH summer temperatures in canopy-covered regions aremore » more consistent with observations and are attributed to two factors. Firstly, CABLE accounts for aerodynamic and radiative interactions between the canopy and the ground below; this placement of the canopy above the ground eliminates the need for a separate bare ground tile in canopy-covered areas. Secondly, CABLE simulates larger evapotranspiration fluxes and a slightly larger daytime cloud cover fraction. Warmer NH winter temperatures result from the parameterization of cold climate processes in CABLE in snow-covered areas. In particular, prognostic snow density increases through the winter and lowers the diurnally resolved snow albedo; variable snow thermal conductivity prevents early winter heat loss but allows more heat to enter the ground as the snow season progresses; liquid precipitation freezing within the snowpack delays the building of the snowpack in autumn and accelerates snow melting in spring. Altogether we find that the ACCESS simulation of surface air temperature benefits from the specific representation of the turbulent transport within and just above the canopy in the roughness sublayer as well as the more complex snow scheme in CABLE relative to MOSES.« less

Echinacea purpurea and Allium sativum as immunostimulants in fish culture using Nile tilapia (Oreochromis niloticus).

PubMed

Aly, S M; Mohamed, M F

2010-10-01

The study was conducted to evaluate the efficiency of echinacea (E) and garlic (G) supplemented diets as immunostimulant for tilapia (Oreochromis niloticus). Seven treatments were designed including a control (C). Fish were fed on 35% protein diet at a rate of 3% body weight per day. Echinacea (1.0 ppt) and garlic (3%) were incorporated in the feed, which was administered for periods of 1, 2 and 3 months (summer season), followed by basal diet for 4 more months (winter season). Neutrophil adherence and haematocrit values increased in both supplemented groups with prolonging period of application. The neutrophils adherence was significantly increased in all treatments except group administered echinacea for 1 month. The lymphocytic counts were significantly (p < 0.004) elevated that resulted in a significant increase in the total leucocytic count in groups administered echinacea for 1 and 2 months when compared with the control and/or other treatments. The gain in the body weight and specific growth rate was significantly increased in all supplemented groups (p < 0.004) during summer, but remained without any significant increase after winter. The survival rate was significantly high (>85%) in all the supplemented groups. The percentage of protection, after challenge infection using pathogenic Aeromonas hydrophila was the highest in groups supplemented with echinacea and garlic for 3 months after summer and winter seasons. It could be concluded that echinacea and garlic improve the gain in body weight, survival rate and resistance against challenge infection. Both compounds showed extended effects after withdrawal and improved resistance to cold stress during the winter season. However, a full commercial cost benefit analysis is necessary before recommending their application in aquaculture. © 2010 Blackwell Verlag GmbH.

Effects of mild wintering conditions on body mass and corticosterone levels in a temperate reptile, the aspic viper (Vipera aspis).

PubMed

Brischoux, François; Dupoué, Andréaz; Lourdais, Olivier; Angelier, Frédéric

2016-02-01

Temperate ectotherms are expected to benefit from climate change (e.g., increased activity time), but the impacts of climate warming during the winter have mostly been overlooked. Milder winters are expected to decrease body condition upon emergence, and thus to affect crucial life-history traits, such as survival and reproduction. Mild winter temperature could also trigger a state of chronic physiological stress due to inadequate thermal conditions that preclude both dormancy and activity. We tested these hypotheses on a typical temperate ectothermic vertebrate, the aspic viper (Vipera aspis). We simulated different wintering conditions for three groups of aspic vipers (cold: ~6 °C, mild: ~14 °C and no wintering: ~24 °C) during a one month long period. We found that mild wintering conditions induced a marked decrease in body condition, and provoked an alteration of some hormonal mechanisms involved in emergence. Such effects are likely to bear ultimate consequences on reproduction, and thus population persistence. We emphasize that future studies should incorporate the critical, albeit neglected, winter season when assessing the potential impacts of global changes on ectotherms. Copyright © 2015 Elsevier Inc. All rights reserved.

Seasonal acclimatization of metabolism in Eurasian tree sparrows (Passer montanus).

PubMed

Zheng, Wei-Hong; Li, Ming; Liu, Jin-Song; Shao, Shu-Li

2008-12-01

Acclimatization to winter conditions is an essential prerequisite for survival of small passerines of the northern temperate zone. Changes in photoperiod, ambient temperature and food availability trigger seasonal acclimatization in physiology and behavior of many birds. In the present study, seasonal adjustments in several physiological, hormonal, and biochemical markers were examined in wild-captured Eurasian tree sparrows (Passer montanus) from the Heilongjiang Province in China. In winter sparrows had higher body mass and basal metabolic rate (BMR). Consistently, the dry mass of liver, heart, gizzard, small intestine, large intestine and total digestive tract were higher in winter than in that in summer. The contents of mitochondrial protein in liver, and state-4 respiration and cytochrome c oxidase (COX) activity in liver and muscle increased significantly in winter. Circulating level of serum triiodothyronine (T3) was significantly higher in winter than in summer. Together, these data suggest that tree sparrows mainly coped with cold by enhancing thermogenic capacities through increased organ masses and heightened activity of respiratory enzymes activities. The results support the view that prominent winter increases in BMR are manifestations of winter acclimatization in tree sparrows and that seasonal variation in metabolism in sparrows is similar to that in other small temperate-wintering birds.

Glacioclimatological study of Perennial Ice in the Fuji Ice Cave, Japan. Part I. Seasonal variation and mechanism of maintenance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohata, Tetsuo; Furukawa, Teruo; Higuchi, Keiji

1994-08-01

Perennial cave ice in a cave located at Mt. Fuji in central Japan was studied to investigate the basic characteristics and the cause for existence of such ice under warm ground-level climate considering the ice cave as a thermal and hydrological system. Fuji Ice Cave is a lava tube cave 150 m in length with a collapsed part at the entrance. Measurements from 1984 to 1986 showed that the surface-level change of floor ice occurred due to freezing and melting at the surface and that melting at the bottom of the ice was negligible. The annual amplitude of change inmore » surface level was larger near the entrance. Meterological data showed that the cold air inflow to the cave was strong in winter, but in summer the cave was maintained near 0[degrees]C with only weak inflow of warm air. The predominant wind system was from the entrance to the interior in both winter and summer, but the spatial scale of the wind system was different. Heat budget consideration of the cave showed that the largest component was the strong inflow of subzero dry air mass in winter. Cooling in winter was compensated for by summer inflow of warm air, heat transport from the surrounding ground layer, and loss of sensible heat due to cooling of the cave for the observed year. Strong inflow of cold air and weak inflow of warm air, which is extremely low compared to the ground level air, seemed to be the most important condition. Thus the thermal condition of the cave is quasi-balanced at the presence condition below 0[degrees]C with ice. It can be said that the interrelated result of the climatological and special structural conditions makes this cave very cold, and allows perennial ice to exist in the cave. Other climatological factors such as precipitation seem to be minor factors. 17 refs., 3 figs., 3 tabs.« less

Beneficial effect of hot spring bathing on stress levels in Japanese macaques.

PubMed

Takeshita, Rafaela S C; Bercovitch, Fred B; Kinoshita, Kodzue; Huffman, Michael A

2018-05-01

The ability of animals to survive dramatic climates depends on their physiology, morphology and behaviour, but is often influenced by the configuration of their habitat. Along with autonomic responses, thermoregulatory behaviours, including postural adjustments, social aggregation, and use of trees for shelter, help individuals maintain homeostasis across climate variations. Japanese macaques (Macaca fuscata) are the world's most northerly species of nonhuman primates and have adapted to extremely cold environments. Given that thermoregulatory stress can increase glucocorticoid concentrations in primates, we hypothesized that by using an available hot spring, Japanese macaques could gain protection against weather-induced cold stress during winter. We studied 12 adult female Japanese macaques living in Jigokudani Monkey Park, Japan, during the spring birth season (April to June) and winter mating season (October to December). We collected faecal samples for determination of faecal glucocorticoid (fGC) metabolite concentrations by enzyme immunoassay, as well as behavioural data to determine time spent in the hot springs, dominance rank, aggression rates, and affiliative behaviours. We used nonparametric statistics to examine seasonal changes in hot spring bathing, and the relationship between rank and air temperature on hot spring bathing. We used general linear mixed-effect models to examine factors impacting hormone concentrations. We found that Japanese macaques use hot spring bathing for thermoregulation during the winter. In the studied troop, the single hot spring is a restricted resource favoured by dominant females. High social rank had both costs and benefits: dominant females sustained high fGC levels, which were associated with high aggression rates in winter, but benefited by priority of access to the hot spring, which was associated with low fGC concentrations and therefore might help reduce energy expenditure and subsequent body heat loss. This unique habit of hot spring bathing by Japanese macaques illustrates how behavioural flexibility can help counter cold climate stress, with likely implications for reproduction and survival.

Analytical methods to predict liquid congealing in ram air heat exchangers during cold operation

NASA Astrophysics Data System (ADS)

Coleman, Kenneth; Kosson, Robert

1989-07-01

Ram air heat exchangers used to cool liquids such as lube oils or Ethylene-Glycol/water solutions can be subject to congealing in very cold ambients, resulting in a loss of cooling capability. Two-dimensional, transient analytical models have been developed to explore this phenomenon with both continuous and staggered fin cores. Staggered fin predictions are compared to flight test data from the E-2C Allison T56 engine lube oil system during winter conditions. For simpler calculations, a viscosity ratio correction was introduced and found to provide reasonable cold ambient performance predictions for the staggered fin core, using a one-dimensional approach.

Overwintering Biology of Culex (Diptera: Culicidae) Mosquitoes in the Sacramento Valley of California

PubMed Central

NELMS, BRITTANY M.; MACEDO, PAULA A.; KOTHERA, LINDA; SAVAGE, HARRY M.; REISEN, WILLIAM K.

2014-01-01

At temperate latitudes, Culex (Diptera: Culicidae) mosquitoes typically overwinter as adult females in reproductive arrest and also may serve as reservoir hosts for arboviruses when cold temperatures arrest viral replication. To evaluate their role in the persistence of West Nile virus (WNV) in the Sacramento Valley of California, the induction and termination of diapause were investigated for members of the Culex pipiens (L.) complex, Culex tarsalis Coquillett, and Culex stigmatosoma Dyar under field, seminatural, and experimental conditions. All Culex spp. remained vagile throughout winter, enabling the collection of 3,174 females and 1,706 males from diverse habitats during the winters of 2010–2012. Overwintering strategies included both quiescence and diapause. In addition, Cx. pipiens form molestus Forskäl females remained reproductively active in both underground and aboveground habitats. Some blood-fed, gravid, and parous Cx. tarsalis and Cx. pipiens complex females were collected throughout the winter period. Under both field and experimental conditions, Cx. tarsalis and Cx. stigmatosoma females exposed to autumnal conditions arrested primary follicular maturation at previtellogenic stage I, with primary to secondary follicular ratios <1.5 (indicative of a hormonally induced diapause). In contrast, most Cx. pipiens complex females did not enter reproductive diapause and ovarian follicles matured to ≥stage I–II (host-seeking arrest) or were found in various stages of degeneration. Diapause was initiated in the majority of Cx. tarsalis and Cx. stigmatosoma females by mid-late October and was terminated after the winter solstice, but host-seeking seemed limited by temperature. An accrual of 97.52 ± 30.7 and 162.85 ± 79.3 degree-days after the winter solstice was estimated to be necessary for diapause termination in Cx. tarsalis under field and seminatural conditions, respectively. An increase in the proportion of blood-fed Culex females in resting collections occurred concurrently with diapause termination in field populations based on ovarian morphometrics. WNV RNA was detected in one pool of 18 males and in a single blood-fed female Cx. tarsalis collected during winter. Therefore, both vertically and horizontally infected Culex females may persist through winter and possibly transmit WNV after diapause termination in late winter or early spring in the Sacramento Valley of California. PMID:23926775

Double diffusion in the frontal zones of the Yellow and East China Seas in winter

NASA Astrophysics Data System (ADS)

Oh, K.; Lee, S.

2017-12-01

Where the cold, fresh water of the Yellow Sea (YS) and the warm, salty water of the East China Sea (ECS) meet, northern and southern fronts are formed in the southeastern YS and the northwestern ECS, respectively. Strong thermohaline fronts are formed on the northern front, and a strong thermocline and a temperature reversal phenomenon are represented in this front. To understand the water structure of this thermohaline zone, we examined double diffusion in the frontal zones in February 2003 using hydrographic data. In the northern front, the warm, salty Cheju Warm Current Water (CWCW) moved northwards along the bottom layer and the cold, fresh Yellow Sea Cold Water (YSCW) flowed southward in the upper layer. As a result, strong thermohaline fronts forms in the area where the two water masses met, and the slope was developed downward across the front. In this area, a strong thermocline and temperature reversal structures were present. The cold, fresh Korean Coastal Water (KCW) was also found in the upper layer near the thermocline, and has a low-temperature, low-salinity more than surrounding water. When cold, fresh water is located over warm, salty water, heat diffuses through the interface between the two water masses, and then the diffusive-convection can be expected to occur. On the other hand, when warm, salty water overlays cold, fresh water, heat in the upper layer is preferentially transferred downward, and the salt-fingering occurs. The diffusive-convection occurs predominantly in the northern thermohaline front, where the cold, fresh YSCW is situated above the warm, salty CWCW and has the effect of strengthening stratification, so that the water column maintains a physically stable structure. In addition, this phenomenon seems to play a role in maintaining the reversal structure. The salt-fingering occurs in upper layers of the northern front where the cold, fresh YSCW is located over the most cold, fresh KCW. Near the northern thermo-halocline zone, the salt-fingering occurs simultaneously with the diffusive-convection, because three water masses, YSCW, KCW and CWCW, interact in that area. Therefore, it can be seen that the water structure of the northern frontal zone in winter is influenced mainly by the cold, fresh YSCW, the most cold, fresh KCW, and the warm, salty CWCW.

Winter Snowfall Turns an Emerald White

NASA Technical Reports Server (NTRS)

2001-01-01

Ireland's climate is normally mild due to the nearby Gulf Stream, but the waning days of 2000 saw the Emerald Isle's green fields swathed in an uncommon blanket of white. The contrast between summer and winter is apparent in this pair of images of southwestern Ireland acquired by MISR's vertical-viewing (nadir) camera on August 23, 2000 (left) and December 29, 2000 (right). The corresponding Terra orbit numbers are 3628 and 5492, respectively.

The year 2000 brought record-breaking weather to the British Isles. England and Wales experienced the wettest spring and autumn months since 1766. Despite being one of the warmest years in recent history, a cold snap arrived between Christmas and New Year's Day. According to the UK Meteorological Office, the 18 centimeters (7 inches) of snow recorded at Aldergrove, Northern Ireland, on December 27-28 was the deepest daily fall since 1930.

Prominent geographical features visible in the MISR images include Galway Bay near the top left. Further south, the mouth of the River Shannon, the largest river in the British Isles, meets the Atlantic Ocean. In the lower portions of the images are the counties of Limerick, Kerry and Cork.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology

Endless cold: a seasonal reconstruction of temperature and precipitation in the Burgundian Low Countries during the 15th century based on documentary evidence

NASA Astrophysics Data System (ADS)

Camenisch, C.

2015-08-01

This paper applies the methods of historical climatology to present a climate reconstruction for the area of the Burgundian Low Countries during the 15th century. The results are based on documentary evidence that has been handled very carefully, especially with regard to the distinction between contemporary and non-contemporary sources. Approximately 3000 written records derived from about 100 different sources were examined and converted into seasonal seven-degree indices for temperature and precipitation. For the Late Middle Ages only a few climate reconstructions exist. There are even fewer reconstructions which include spring and autumn temperature or any precipitation information at all. This paper therefore constitutes a useful contribution to the understanding of climate and weather conditions in the less well researched but highly interesting 15th century. The extremely cold winter temperatures during the 1430s and an extremely cold winter in 1407/1408 are striking. Moreover, no other year in this century was as hot and dry as 1473. At the beginning and the end of the 1480s and at the beginning of the 1490s summers were considerably wetter than average.

Differential expression and emerging functions of non-coding RNAs in cold adaptation.

PubMed

Frigault, Jacques J; Morin, Mathieu D; Morin, Pier Jr

2017-01-01

Several species undergo substantial physiological and biochemical changes to confront the harsh conditions associated with winter. Small mammalian hibernators and cold-hardy insects are examples of natural models of cold adaptation that have been amply explored. While the molecular picture associated with cold adaptation has started to become clearer in recent years, notably through the use of high-throughput experimental approaches, the underlying cold-associated functions attributed to several non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), remain to be better characterized. Nevertheless, key pioneering work has provided clues on the likely relevance of these molecules in cold adaptation. With an emphasis on mammalian hibernation and insect cold hardiness, this work first reviews various molecular changes documented so far in these processes. The cascades leading to miRNA and lncRNA production as well as the mechanisms of action of these non-coding RNAs are subsequently described. Finally, we present examples of differentially expressed non-coding RNAs in models of cold adaptation and elaborate on the potential significance of this modulation with respect to low-temperature adaptation.

March-June temperature reconstruction in the Czech Lands based on cereal harvest dates in the 1501-2008 period

NASA Astrophysics Data System (ADS)

Brázdil, Rudolf; Možný, Martin; Dobrovolný, Petr; Trnka, Mirek

2010-05-01

Cereal crop harvests reflect the weather patterns of the period immediately preceding them, and thus the dates at which they begin may be used as a source of proxy data on regional climate. Using systematic phenological observations in the Czech Lands (now known as the Czech Republic) after 1848, together with exploration of further surviving documentary evidence (chronicles, diaries, financial accounts etc.), it has proved possible to create series of winter wheat harvest dates for the period 1501-2008. Employing linear regression, the harvesting dates of the main cereal species (wheat, rye, barley, oats) were first converted to winter wheat harvest days and then normalised to the same altitude above sea level. The next step consisted of using series of winter wheat harvest dates to reconstruct mean March-June temperatures in the Czech Lands, applying standard palaeoclimatological methods. Series reconstructed by linear regression explain 70% of temperature variability. A profound cold period corresponding with late winter wheat harvests was noted between 1659 and 1705. In contrast, warm periods (i.e. early winter wheat harvests) were found for the periods of 1517-1542, 1788-1834 and 1946-2008. The period after 1951 is the warmest of all throughout the entire 1501-2008 period. Comparisons with other European temperature reconstructions derived from documentary sources (including grape harvest dates), tree-ring and instrumental data reveal generally close agreement, with significant correlations. Lower correlations around A.D. 1650 and 1750 may be partly related to deterioration of socio-economic conditions in the Czech Lands resulting from prolonged wars. The results obtained demonstrate that it is possible to use widely-available cereal harvest data for climate analysis and also that such data constitute an independent proxy data series for the region of Central Europe crucial to further studies of the potential impact of climatic variability and climate change on agriculture. (The paper was supported by Grant Agency of the Czech Republic, project No. 521/08/1682.)

European temperature responses to blocking and ridge regional patterns

NASA Astrophysics Data System (ADS)

Sousa, Pedro M.; Trigo, Ricardo M.; Barriopedro, David; Soares, Pedro M. M.; Santos, João A.

2018-01-01

Blocking occurrence and its impacts on European temperature have been studied in the last decade. However, most previous studies on blocking impacts have focused on winter only, disregarding its fingerprint in summer and differences with other synoptic patterns that also trigger temperature extremes. In this work, we provide a clear distinction between high-latitude blocking and sub-tropical ridges occurring in three sectors of the Euro-Atlantic region, describing their climatology and consequent impacts on European temperature during both winter and summer. Winter blocks (ridges) are generally associated to colder (warmer) than average conditions over large regions of Europe, in some areas with anomalies larger than 5 °C, particularly for the patterns occurring in the Atlantic and Central European sectors. During summer, there is a more regional response characterized by above average temperature for both blocking and ridge patterns, especially those occurring in continental areas, although negative temperature anomalies persist in southernmost areas during blocking. An objective analysis of the different forcing mechanisms associated to each considered weather regime has been performed, quantifying the importance of the following processes in causing the temperature anomalies: horizontal advection, vertical advection and diabatic heating. While during winter advection processes tend to be more relevant to explain temperature responses, in summer radiative heating under enhanced insolation plays a crucial role for both blocking and ridges. Finally, the changes in the distributions of seasonal temperature and in the frequencies of extreme temperature indices were also examined for specific areas of Europe. Winter blocking and ridge patterns are key drivers in the occurrence of regional cold and warm extreme temperatures, respectively. In summer, they are associated with substantial changes in the frequency of extremely warm days, but with different signatures in southern Europe. We conclude that there has been some misusage of the traditional blocking definition in the attribution of extreme events.

Influence of sky view factor on outdoor thermal environment and physiological equivalent temperature

NASA Astrophysics Data System (ADS)

He, Xiaodong; Miao, Shiguang; Shen, Shuanghe; Li, Ju; Zhang, Benzhi; Zhang, Ziyue; Chen, Xiujie

2015-03-01

Sky view factor (SVF), which is an indicator of urban canyon geometry, affects the surface energy balance, local air circulation, and outdoor thermal comfort. This study focused on a continuous and long-term meteorological observation system to investigate the effects of SVF on outdoor thermal conditions and physiological equivalent temperature (PET) in the central business district (CBD) of Beijing (which is located within Chaoyang District), specifically addressed current knowledge gaps for SVF-PET relationships in cities with typical continental/microthermal climates. An urban sub-domain scale model and the RayMan model were used to diagnose wind fields and to calculate SVF and long-term PET, respectively. Analytical results show that the extent of shading contributes to variations in thermal perception distribution. Highly shaded areas (SVF <0.3) typically exhibit less frequent hot conditions during summer, while enduring longer periods of cold discomfort in winter than moderately shaded areas (0.3< SVF <0.5) and slightly shaded areas (SVF >0.5), and vice versa. Because Beijing has a monsoon-influenced humid continental climate with hot summers and long, cold, windy, and dry winters, a design project that ideally provides moderate shading should be planned to balance hot discomfort in summer and cold discomfort in winter, which effectively prolongs the comfort periods in outdoor spaces throughout the entire year. This research indicate that climate zone characteristics, urban environmental conditions, and thermal comfort requirements of residents must be accounted for in local-scale scientific planning and design, i.e., for urban canyon streets and residential estates.

Altered snowfall and soil disturbance influence the early life stage transitions and recruitment of a native and invasive grass in a cold desert.

PubMed

Gornish, Elise S; Aanderud, Zachary T; Sheley, Roger L; Rinella, Mathew J; Svejcar, Tony; Englund, Suzanne D; James, Jeremy J

2015-02-01

Climate change effects on plants are expected to be primarily mediated through early life stage transitions. Snowfall variability, in particular, may have profound impacts on seedling recruitment, structuring plant populations and communities, especially in mid-latitude systems. These water-limited and frequently invaded environments experience tremendous variation in snowfall, and species in these systems must contend with harsh winter conditions and frequent disturbance. In this study, we examined the mechanisms driving the effects of snowpack depth and soil disturbance on the germination, emergence, and establishment of the native Pseudoroegnaria spicata and the invasive Bromus tectorum, two grass species that are widely distributed across the cold deserts of North America. The absence of snow in winter exposed seeds to an increased frequency and intensity of freeze-thaw cycles and greater fungal pathogen infection. A shallower snowpack promoted the formation of a frozen surface crust, reducing the emergence of both species (more so for P. spicata). Conversely, a deeper snowpack recharged the soil and improved seedling establishment of both species by creating higher and more stable levels of soil moisture availability following spring thaw. Across several snow treatments, experimental disturbance served to decrease the cumulative survival of both species. Furthermore, we observed that, regardless of snowpack treatment, most seed mortality (70-80%) occurred between seed germination and seedling emergence (November-March), suggesting that other wintertime factors or just winter conditions in general limited survival. Our results suggest that snowpack variation and legacy effects of the snowpack influence emergence and establishment but might not facilitate invasion of cold deserts.

Effect of season on peripheral resistance to localised cold stress

NASA Astrophysics Data System (ADS)

Tanaka, M.; Harimura, Y.; Tochihara, Y.; Yamazaki, S.; Ohnaka, T.; Matsui, J.; Yoshida, K.

1984-03-01

This study was carried out to determine the effect that seasonal changes have on the effect of localised cold stress on peripheral temperatures using the foot immersion method with a cold water bath. The subjects were six males and four females. The data were obtained in April, July, October and January. Skin temperature of the right index finger, the forehead, the arm, the cheek, the second toe and the instep were measured before, during and after the immersion of the feet in water at 15°C for 10 mins, as well as oxygen consumption before immersion of the feet. The average finger temperature was highest during foot immersion in the summer, next highest in the winter, then spring, and the lowest during foot immersion in the autumn. The finger temperatures during the pre-immersion period in the autumn tended to be lower than in other seasons. The finger temperatures during the pre-immersion period affected the temperature change of the finger during the immersion period. The rate of increase of the toe temperature and the foot temperature during post-immersion in the summer and the spring were greater than those in the autumn and winter. Oxygen consumption during the pre-immersion period in the autumn was significantly lower than in the other seasons (p<0.001 or 0.010). Cooling the feet caused no significant changes in the temperatures the cheek, forehead or forearm. The cheek temperature in the summer and autumn was cooler than corresponding temperatures taken in the winter and spring.

Winter Habitat Preferences for Florida Manatees and Vulnerability to Cold

PubMed Central

Laist, David W.; Taylor, Cynthia; Reynolds, John E.

2013-01-01

To survive cold winter periods most, if not all, Florida manatees rely on warm-water refuges in the southern two-thirds of the Florida peninsula. Most refuges are either warm-water discharges from power plant and natural springs, or passive thermal basins that temporarily trap relatively warm water for a week or more. Strong fidelity to one or more refuges has created four relatively discrete Florida manatee subpopulations. Using statewide winter counts of manatees from 1999 to 2011, we provide the first attempt to quantify the proportion of animals using the three principal refuge types (power plants, springs, and passive thermal basins) statewide and for each subpopulation. Statewide across all years, 48.5% of all manatees were counted at power plant outfalls, 17.5% at natural springs, and 34.9 % at passive thermal basins or sites with no known warm-water features. Atlantic Coast and Southwest Florida subpopulations comprised 82.2% of all manatees counted (45.6% and 36.6%, respectively) with each subpopulation relying principally on power plants (66.6% and 47.4%, respectively). The upper St. Johns River and Northwest Florida subpopulations comprised 17.8% of all manatees counted with almost all animals relying entirely on springs (99.2% and 88.6% of those subpopulations, respectively). A record high count of 5,076 manatees in January 2010 revealed minimum sizes for the four subpopulations of: 230 manatees in the upper St. Johns River; 2,548 on the Atlantic Coast; 645 in Northwest Florida; and 1,774 in Southwest Florida. Based on a comparison of carcass recovery locations for 713 manatees killed by cold stress between 1999 and 2011 and the distribution of known refuges, it appears that springs offer manatees the best protection against cold stress. Long-term survival of Florida manatees will require improved efforts to enhance and protect manatee access to and use of warm-water springs as power plant outfalls are shut down. PMID:23527063

Processes Controlling Water Vapor in the Winter Arctic Tropopause Region

NASA Technical Reports Server (NTRS)

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Podolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Hipskino, R. Stephen (Technical Monitor)

2001-01-01

This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999-2000 winter season. Aircraft based water vapor, carbon monoxide, and ozone measurements are analyzed so as to establish how deeply tropospheric air mixes into the arctic lower-most stratosphere, and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to- stratosphere exchange extends into the arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases idly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of about 5 ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20\\% of the parcels which have ozone values of 300-350ppbv experiencing ice saturation in a given 10 day period. Third, during early Spring temperatures at the tropopause are cold enough so that 5-10\\% of parcels experience relative humidities above 100\\%, even if the water content is as low as 5 ppmv. The implication is that during, this period the arctic tropopause can play an important role in maintaining a very dry upper troposphere during early Spring.

Processes Controlling Water Vapor in the Winter Arctic Tropopause Region

NASA Technical Reports Server (NTRS)

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Padolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Mahoney, Michael J.; Richard, Erik

2002-01-01

This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE III-Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999/2000 winter season. Aircraft-based water vapor, carbon monoxide, and ozone measurements were analyzed so as to establish how deeply tropospheric air mixes into the Arctic lowermost stratosphere and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to-stratosphere exchange extends into the Arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases with altitude most rapidly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of above 5ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20% of the parcels which have ozone values of 300-350 ppbv experiencing ice saturation in a given 10 day period. Third, during early spring, temperatures at the troposphere are cold enough so that 5-10% of parcels experience relative humidities above 100%, even if the water content is as low as 5 ppmv. The implication is that during this period, dynamical processes near the Arctic tropopause can dehydrate air and keep the Arctic tropopause region very dry during early spring.

Spatial Analysis of Seasonal Dynamics and Overwintering of Drosophila suzukii (Diptera: Drosophilidae) in the Okanagan-Columbia Basin, 2010-2014.

PubMed

Thistlewood, Howard M A; Gill, Paramjit; Beers, Elizabeth H; Shearer, Peter W; Walsh, Doug B; Rozema, Brigitte M; Acheampong, Susanna; Castagnoli, Steve; Yee, Wee L; Smytheman, Peter; Whitener, Alix B

2018-04-05

Spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), was monitored from 2010 to 2014 in 314-828 sites located in interior fruit-growing regions of OR and WA, United States, and BC, Canada, using traps baited with apple cider vinegar or sugar-water-yeast. Seasonal population dynamics and sex ratios were summarized for berry, cherry, stone fruit, grape, non-crop host plants, non-host sites, and for conventional IPM, certified organic, backyard, and feral sites, by region and year. Overwintering was detected in all regions and years, despite winter temperatures below -17°C. A spatial analysis was conducted using a Geographic Information System (GIS), daily weather data, geomorphometric measures of terrain, distance to water, and other variables, at each site. Overwintering success at a site, measured as Julian week of first capture of D. suzukii, was significantly related (R2 = 0.49) in cherry habitats to year, agronomic treatment, and number of winter days with temperatures >-5°C. In berry, cherry, stone fruit and grape habitats, 2011-2014, it was significantly related (R2 = 0.42) to year, agronomic treatment, the logarithm of peak population of D. suzukii in the prior autumn, latitude, elevation, and topographic wetness index. The results show that D. suzukii has adapted to exploit a succession of irrigated crops and feral habitats in mixed landscapes of a semi-arid region with cold winters and hot dry summers, and are shaping strategies for pest management and for biological control.

Stratospheric minor species vertical distributions during polar winter by balloon borne UV-Vis spectrometry

NASA Technical Reports Server (NTRS)

Pommereau, J. P.; Piquard, J.

1994-01-01

A light, relatively cheap and easy to operate balloonborne UV-visible spectrometer was designed for investigating ozone photochemistry in the Arctic winter. The instrument was flown 11 times during the European Arctic Stratospheric Ozone Experiment (EASOE) in winter 1991-92 in Northern Scandinavia. The first simultaneous measurements of vertical distributions of aerosols, PSC's, O3, NO2 and OClO inside the vortex during flight no. 6 on 16 January, in cold conditions are reported, which show that nitrogen oxides were almost absent (lower than 100 ppt) in the stratosphere below 22 km, while a layer of relatively large OClO concentration (15 ppt) was present at the altitude of the minimum temperature.

COLD WEATHER PLUME STUDY

EPA Science Inventory

While many studies of power plant plume transport and transformation have been performed during the summer, few studies of these processes during the winter have been carried out. Accordingly, the U.S. Environmental Protection Agency and the Electric Power Research Institute join...

Trends in Cold Extremes and Winter Weather for the SPTC Region

DOT National Transportation Integrated Search

2017-05-31

Extreme weather poses multifaceted hazards to transportation. There is now increased awareness of the threats of climate variability and change on transportation safety and state of good repair. In particular, a non-stationary climate will potentiall...

[Comparison of air/soil mercury exchange between warm and cold season in Hongfeng Reservoir region].

PubMed

Wang, Shao-feng; Feng, Xin-bin; Qiu, Guang-le; Fu, Xue-wu

2004-01-01

In July 2002 and March 2003, the mercury exchange flux between soil and air was measured using dynamic flux chamber method in Hongfeng Reservoir region. Mercury exchange flux is (27.4 +/- 40.1) ng x (m2 x h)(-1) (n = 255) and (5.6 +/- 19.4) ng x (m2 x h)(-1) (n = 192) in summer and winter respectively. The correlation coefficient between mercury flux and solar radiation, air temperature, soil temperature is 0.74, 0.83 and 0.80 in summer, and 0.88, 0.56 and 0.59 in winter. From the data, it was found that the mercury emission is stronger in summer than that in winter, and compared to winter, mercury exchange between soil and air depends more on meteorological conditions in summer.

High-Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zobel, Zachary; Wang, Jiali; Wuebbles, Donald J.

The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary con- ditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal-length time slices (2045–2054 and 2085–2094) are compared with a historical decade (1995–2004). Probabilitymore » density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm-side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm-side shift with decreased variability. Finally, using "business-as-usual" scenario, 5-day heat waves are projected to occur at least 5–10 times per year in most CONUS and ≥ 95°F days will increase by 1–2 months by the end of the century.« less

High-Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States

DOE PAGES

Zobel, Zachary; Wang, Jiali; Wuebbles, Donald J.; ...

2017-11-20

The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary con- ditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal-length time slices (2045–2054 and 2085–2094) are compared with a historical decade (1995–2004). Probabilitymore » density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm-side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm-side shift with decreased variability. Finally, using "business-as-usual" scenario, 5-day heat waves are projected to occur at least 5–10 times per year in most CONUS and ≥ 95°F days will increase by 1–2 months by the end of the century.« less

Risk of Fall-Related Injury due to Adverse Weather Events, Philadelphia, Pennsylvania, 2006-2011.

PubMed

Gevitz, Kathryn; Madera, Robbie; Newbern, Claire; Lojo, José; Johnson, Caroline C

Following a surge in fall-related visits to local hospital emergency departments (EDs) after a severe ice storm, the Philadelphia Department of Public Health examined the association between inclement winter weather events and fall-related ED visits during a 5-year period. Using a standardized set of keywords, we identified fall-related injuries in ED chief complaint logs submitted as part of Philadelphia Department of Public Health's syndromic surveillance from December 2006 through March 2011. We compared days when falls exceeded the winter fall threshold (ie, "high-fall days") with control days within the same winter season. We then conducted matched case-control analysis to identify weather and patient characteristics related to increased fall-related ED visits. Fifteen high-fall days occurred during winter months in the 5-year period. In multivariable analysis, 18- to 64-year-olds were twice as likely to receive ED care for fall-related injuries on high-fall days than on control days. The crude odds of ED visits occurring from 7:00 am to 10:59 am were 70% higher on high-fall days vs control days. Snow was a predictor of a high-fall day: the adjusted odds of snow before a high-fall day as compared with snow before a control day was 13.4. The association between the number of fall-related ED visits and weather-related fall injuries, age, and timing suggests that many events occurred en route to work in the morning. Promoting work closures or delaying openings after severe winter weather would allow time for better snow or ice removal, and including "fall risk" in winter weather advisories might effectively warn morning commuters. Both strategies could help reduce the number of weather-related fall injuries.

Investigation of wintertime cold-air pools and aerosol layers in the Salt Lake Valley using a lidar ceilometer

NASA Astrophysics Data System (ADS)

Young, Joseph Swyler

This thesis investigates the utility of lidar ceilometers, a type of aerosol lidar, in improving the understanding of meteorology and air quality in persistent wintertime stable boundary layers, or cold-air pools, that form in urbanized valley and basin topography. This thesis reviews the scientific literature to survey the present knowledge of persistent cold-air pools, the operating principles of lidar ceilometers, and their demonstrated utility in meteorological investigations. Lidar ceilometer data from the Persistent Cold-Air Pool Study (PCAPS) are then used with meteorological and air quality data from other in situ and remote sensing equipment to investigate cold-air pools that formed in Utah's Salt Lake Valley during the winter of 2010-2011. The lidar ceilometer is shown to accurately measure aerosol layer depth and aerosol loading, when compared to visual observations. A linear relationship is found between low-level lidar backscatter and surface particulate measurements. Convective boundary layer lidar analysis techniques applied to cold-air pool ceilometer profiles can detect useful layer characteristics. Fine-scale waves are observed and analyzed within the aerosol layer, with emphasis on Kelvin-Helmholz waves. Ceilometer aerosol backscatter profiles are analyzed to quantify and describe mixing processes in persistent cold-air pools. Overlays of other remote and in-situ observations are combined with ceilometer particle backscatter to describe specific events during PCAPS. This analysis describes the relationship between the aerosol layer and the valley inversion as well as interactions with large-scale meteorology. The ceilometer observations of hydrometers are used to quantify cloudiness and precipitation during the project, observing that 50% of hours when a PCAP was present had clouds or precipitation below 5 km above ground level (AGL). Then, combining an objective technique for determining hourly aerosol layer depths and correcting this subjectively during periods with low clouds or precipitation, a time series of aerosol depths was obtained. The mean depth of the surface-based aerosol layer during PCAP events was 1861 m MSL with a standard deviation of 135 m. The aerosol layer depth, given the approximate 1300 m altitude of the valley floor, is thus about 550 m, about 46% of the basin depth. The aerosol layer is present during much of the winter and is removed only during strong or prolonged precipitation periods or when surface winds are strong. Nocturnal fogs that formed near the end of high-stability PCAP episodes had a limited effect on aerosol layer depth. Aerosol layer depth was relatively invariant during the winter and during the persistent cold-air pools, while PM10 concentrations at the valley floor varied with bulk atmospheric stability associated primarily with passage of large-scale high- and low-pressure weather systems. PM10 concentrations also increased with cold-air pool duration. Mean aerosol loading in the surface-based aerosol layer, as determined from ceilometer backscatter coefficients, showed weaker variations than those of surface PM10 concentrations, suggesting that ineffective vertical mixing and aerosol layering are present in the cold-air pools. This is supported by higher time-resolution backscatter data, and it distinguishes the persistent cold-air pools from well-mixed convective boundary layers where ground-based air pollution concentrations are closely related to time-dependent convective boundary layer/aerosol depths. These results are discussed along with recommendations for future explorations of the ceilometer and cold-air pool topics.

Hawaiian Winter Workshop Proceedings of Parameterization of Small-Scale Processes Held in Manoa, Hawaii on 17-20 January 1989

DTIC Science & Technology

1989-01-01

England while waiting for an outbreak of cold air (Larson, 1988). Even before the arrival of the storm trailing the cold air behind it, both shear and...and simulation of storm -induced mixed-layer deepening. J. Phys. Oceanogr., 8. 582-599. 217 Riley, J.J., and R.W. Metcalf: 1987. Direct numerical...the severe downslope wind storm which occurs in the lee of major mountain barriers (Lilly and Kennedy, 1973: Lilly. 1978) under suitable atmospheric

Bibliography on Cold Regions Science and Technology, Volume 46, Part 2, 1992

DTIC Science & Technology

1992-01-01

Modelling of heat capacity-temperature data for sucrose- conditions: trial study . Peck, L.. 1)992. 15p.. eng) Comparison of four cold hardiness tests on...authors are listed along with the title, date, pagination, and language of the document and the accession number. The subject index is composed of four ...eng1 46-1074 Radar backscatter measurements during the Winter Weddell Abramov Glacier and the runoff in its basin (1989. p.85- Aakjaer. P.D. Gyre Study

Chemistry and dynamics of the Arctic winter 2015/2016: Simulations with the Chemistry-Climate Model EMAC

NASA Astrophysics Data System (ADS)

Khosrawi, Farahnaz; Kirner, Ole; Sinnhuber, Bjoern-Martin; Ruhnke, Roland; Hoepfner, Michael; Woiwode, Wolfgang; Oelhaf, Hermann; Santee, Michelle L.; Manney, Gloria L.; Froidevaux, Lucien; Murtagh, Donal; Braesicke, Peter

2016-04-01

Model simulations of the Arctic winter 2015/2016 were performed with the atmospheric chemistry-climate model ECHAM5/MESSy Atmospheric Chemistry (EMAC) for the POLSTRACC (Polar Stratosphere in a Changing Climate) project. The POLSTRACC project is a HALO mission (High Altitude and LOng Range Research Aircraft) that aims to investigate the structure, composition and evolution of the Arctic Upper Troposphere Lower Stratosphere (UTLS) in a changing climate. Especially, the chemical and physical processes involved in Arctic stratospheric ozone depletion, transport and mixing processes in the UTLS at high latitudes, polar stratospheric clouds as well as cirrus clouds are investigated. The model simulations were performed with a resolution of T42L90, corresponding to a quadratic Gaussian grid of approximately 2.8°× 2.8° degrees in latitude and longitude, and 90 vertical layers from the surface up to 0.01 hPa (approx. 80 km). A Newtonian relaxation technique of the prognostic variables temperature, vorticity, divergence and surface pressure towards ECMWF data was applied above the boundary layer and below 10 hPa, in order to nudge the model dynamics towards the observed meteorology. During the Arctic winter 2015/2016 a stable vortex formed in early December, with a cold pool where temperatures reached below the Nitric Acid Trihydrate (NAT) existence temperature of 195 K, thus allowing Polar Stratospheric Clouds (PSCs) to form. The early winter has been exceptionally cold and satellite observations indicate that sedimenting PSC particles have lead to denitrification as well as dehydration of stratospheric layers. In this presentation an overview of the chemistry and dynamics of the Arctic winter 2015/2016 as simulated with EMAC will be given and comparisons to satellite observations such as e.g. Aura/MLS and Odin/SMR will be shown.