Occurrence and synoptic background of strong and very strong frost in spring and autumn in Central Europe

Abstract The objective of the paper was the determination of the circulation conditions of occurrence of strong and very strong frost in Central Europe. A frost day was defined as a day with the minimum temperature lower than 0 °C and maximum temperature higher than 0 °C. Moreover, a division of frost was performed in terms of value of minimum temperature, resulting in the designation of mild frost (up to − 2.0 °C), moderate frost (from − 2.1 to − 4 °C), strong frost (from − 4.1 to − 6 °C) and very strong frost (< − 6 °C). The study was based on data from the years 1966–2015 from the Institute of Meteorology and Water Management—National Research Institute, Deutscher Wetterdienst and National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). The analysis of baric conditions employed values of pressure at sea level, height of isobaric surface of 500 hPa and air temperature at a level of 850 hPa, as well as their anomalies. The spatial analysis showed that the number of frost days in spring and autumn increased from the west to the east of Central Europe. A decrease in the number of frost days, however, is observed over the prevailing area. Average conditions favouring the occurrence of strong and very strong frost both in spring and autumn were related to higher than average pressure at sea level over the prevailing area of the Euro-Atlantic sector. Such baric conditions caused advections of cool air masses from the northern sector.

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NOCE MROŹNE W POZNANIU I ICH CYRKULACYJNE UWARUNKOWANIA

Badania Fizjograficzne nad Polska Zachodnia ◽

10.14746/bfg.2018.9.17 ◽

2018 ◽

pp. 225-238

Author(s):

ARKADIUSZ M. TOMCZYK

Keyword(s):

Water Management ◽

High Pressure ◽

Central Europe ◽

Air Temperature ◽

National Research Institute ◽

Pressure System ◽

Air Masses ◽

Circulation Types ◽

Pressure Ridge ◽

Minimum Air Temperature

The main purpose of this article was to determine the pressure situations and circulation types causing the occurrence of frosty nights in Poznań in the years 1966/67–2015/16. A night was assumed to be a frosty night with a minimum temperature below –10°C. The article uses the daily values of the minimum air temperature for the period of 1966–2016 for the station in Poznań. The data was provided by the Institute of Meteorology and Water Management – National Research Institute. In the analyzed years, 10 frosty nights were recorded on average every season. Conducted studies showed a decrease in their number, although these changes were not statistically significant. The average occurrence of frosty nights was associated with the presence of a high-pressure system over Central Europe, which developed within a high-pressure ridge extending over the majority of the continent. Such a pressure situation led to the advection of continental air masses from the eastern sector.

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Impact of Atmospheric Circulation on the Occurrence of Hot Nights in Central Europe

Atmosphere ◽

10.3390/atmos9120474 ◽

2018 ◽

Vol 9 (12) ◽

pp. 474 ◽

Cited By ~ 4

Author(s):

Arkadiusz Tomczyk

Keyword(s):

Water Management ◽

High Pressure ◽

Central Europe ◽

National Research Institute ◽

Upper Troposphere ◽

Atmospheric Research ◽

Pressure Area ◽

Environmental Prediction ◽

The Waves ◽

Minimum Air Temperature

The main goal of the study is to determine the pressure conditions that cause waves of hot nights in Central Europe. The goal was implemented on the basis of data from 1966 to 2015, made available by the Institute of Meteorology and Water Management—National Research Institute, Deutscher Wetterdienst and the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). A hot night was defined as a day with the minimum air temperature above 18 °C. In the analysed years, an increase in the number of hot nights was found, which was predominantly statistically significant within the studied area. The study shows that the occurrence of waves of hot nights in Central Europe was associated on average with the ridge of high pressure, within which a local high-pressure area developed. During the waves of hot nights, there were positive anomalies of heights of isobaric surfaces over the study area with a maximum in the upper troposphere.

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Episódios e gênese dos eventos climáticos extremos em Goiânia-GO / Episodes and genesis of extreme climate events in Goiânia-GO

Caderno de Geografia ◽

10.5752/p.2318-2962.2019v29n57p583-608 ◽

2019 ◽

Vol 29 (57) ◽

pp. 583-608

Author(s):

Diego Nascimento ◽

Luan Victor Lima ◽

Vitor Cruz

Keyword(s):

Relative Humidity ◽

Extreme Events ◽

Minimum Temperature ◽

Summer Precipitation ◽

South Atlantic Convergence Zone ◽

Early Spring ◽

Maximum Temperature ◽

Late Winter ◽

Air Masses ◽

Autumn And Winter

Sob a abordagem da climatologia geográfica, que leva em consideração a dinâmica das massas de ar na análise do ritmo e da gênese do clima, o presente trabalho busca apresentar os episódios de eventos climáticos extremos ocorridos em Goiânia-GO e abordar os mecanismos atmosféricos responsáveis pela gênese dos mesmos. Os eventos extremos foram levantados a partir de dados diários precipitação, temperatura máxima e mínima e umidade relativa do ar, registrados pela estação meteorológica do Instituto Nacional de Meteorologia (INMET), compreendendo a série temporal de 1961 a 2018 (58 anos). A identificação dos mecanismos atmosféricos atuantes nos dias dos episódios extremos foi realizada a partir da leitura e interpretação de cartas sinóticas da Marinha do Brasil, tendo como base o recorte temporal de 2012 a 2018. Foi possível apontar a ocorrência de eventos extremos em períodos específicos do ano, como no caso de eventos de precipitação no verão, sob influência da Massa equatorial continental e da Zona de Convergência do Atlântico Sul; de temperatura máxima no final do inverno e início da primavera, quando predomina a Massa equatorial continental e a Massa tropical Atlântica; de temperatura mínima no outono e inverno, condicionados pela incursão da Massa polar; de umidade relativa do ar no inverno, ocorrendo devido a atuação dos sistemas atmosféricos que habitualmente definem a condição sinótica em Goiânia.Palavras–chave: eventos extremos, massas de ar, fatores, mecanismos, impactos.Abstract Under the approach of Geographical Climatology, which takes into account the dynamics of the air masses in the analysis of the rhythm and the genesis of the climate, the present work seeks to present the episodes of extreme climatic events occurring in Goiânia-GO and to indicate the atmospheric mechanisms responsible for the genesis of this events. The extreme events were listed from daily precipitation, maximum and minimum temperature and relative humidity data, recorded by the meteorological station of the National Institute of Meteorology, comprising the time series from 1961 to 2018 (58 years). The identification of the atmospheric mechanisms acting on the days of the extreme episodes was performed from the reading and interpretation of Brazilian Navy's synoptic charts, based on the temporal cut from 2012 to 2018. It was possible to indicate the occurrence of extreme events in specific periods of the year, as in the case of summer precipitation events, under the influence of Continental equatorial mass and South Atlantic Convergence Zone; of maximum temperature in late winter and early spring, when Continental equatorial mass and Atlantic tropical mass predominate; of minimum temperature in autumn and winter, conditioned by the incursion of Polar mass; of relative humidity of the air in the winter, occurring due to the performance of the atmospheric systems that habitually define the synoptic condition in Goiânia.Keywords: extreme events, air masses, factors, mechanisms, impacts

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The Barents Ice Sheet as a Relay Regulator of Glacial-Interglacial Alternation

Quaternary Research ◽

10.1016/0033-5894(78)90034-0 ◽

1978 ◽

Vol 9 (3) ◽

pp. 288-299 ◽

Cited By ~ 26

Author(s):

D. D. Kvasov

Keyword(s):

Kola Peninsula ◽

Sea Level ◽

Central Europe ◽

Ice Sheets ◽

Ice Sheet ◽

Air Masses ◽

The North ◽

Pechora River ◽

Pechora River Basin ◽

Vast Area

A slight cooling can induce the formation of ice sheets in the Scandinavian mountains and in the American Arctic. The increasing albedo and the appearance of cold air masses above the glaciers cause glaciation to spread over a vast area. As a result, the sea level lowers and a large part of the Barents and Kara seabeds dries up. Ice sheets are formed there, which spread over the northeastern part of the Kola Peninsula, the Pechora River basin, and over northwestern Siberia. The glacier barrier extending nearly from the North Pole to central Europe hinders latitudinal atmospheric circulation. Precipitation decreases sharply in the areas east and southeast of the glaciers. As a consequence, glaciers in the mid-latitudes retreat and sea level rises. Increased iceberg formation is induced in the periphery of the Barents Ice Sheet, causing it to disappear. An interglacial sets in.

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AnANN Model Trained on Regional Data in the Prediction of Particular Weather Conditions

Applied Sciences ◽

10.3390/app11114757 ◽

2021 ◽

Vol 11 (11) ◽

pp. 4757

Author(s):

Aleksandra Bączkiewicz ◽

Jarosław Wątróbski ◽

Wojciech Sałabun ◽

Joanna Kołodziejczyk

Keyword(s):

Atmospheric Pressure ◽

Real Life ◽

Real Data ◽

Weather Conditions ◽

Maximum Temperature ◽

Air Masses ◽

Weather Forecasts ◽

Life Problems ◽

The World ◽

The City

Artificial Neural Networks (ANNs) have proven to be a powerful tool for solving a wide variety of real-life problems. The possibility of using them for forecasting phenomena occurring in nature, especially weather indicators, has been widely discussed. However, the various areas of the world differ in terms of their difficulty and ability in preparing accurate weather forecasts. Poland lies in a zone with a moderate transition climate, which is characterized by seasonality and the inflow of many types of air masses from different directions, which, combined with the compound terrain, causes climate variability and makes it difficult to accurately predict the weather. For this reason, it is necessary to adapt the model to the prediction of weather conditions and verify its effectiveness on real data. The principal aim of this study is to present the use of a regressive model based on a unidirectional multilayer neural network, also called a Multilayer Perceptron (MLP), to predict selected weather indicators for the city of Szczecin in Poland. The forecast of the model we implemented was effective in determining the daily parameters at 96% compliance with the actual measurements for the prediction of the minimum and maximum temperature for the next day and 83.27% for the prediction of atmospheric pressure.

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Spatiotemporal Evolution of Fractional Vegetation Cover and Its Response to Climate Change Based on MODIS Data in the Subtropical Region of China

Remote Sensing ◽

10.3390/rs13050913 ◽

2021 ◽

Vol 13 (5) ◽

pp. 913

Author(s):

Hua Liu ◽

Xuejian Li ◽

Fangjie Mao ◽

Meng Zhang ◽

Di’en Zhu ◽

...

Keyword(s):

Vegetation Cover ◽

Minimum Temperature ◽

Maximum Temperature ◽

Distribution Area ◽

Spatiotemporal Pattern ◽

Climate Factors ◽

Important Indicator ◽

Fractional Vegetation Cover ◽

Annual Minimum Temperature ◽

Total Study Area

The subtropical vegetation plays an important role in maintaining the structure and function of global ecosystems, and its contribution to the global carbon balance are receiving increasing attention. The fractional vegetation cover (FVC) as an important indicator for monitoring environment change, is widely used to analyze the spatiotemporal pattern of regional and even global vegetation. China is an important distribution area of subtropical vegetation. Therefore, we first used the dimidiate pixel model to extract the subtropical FVC of China during 2001–2018 based on MODIS land surface reflectance data, and then used the linear regression analysis and the variation coefficient to explore its spatiotemporal variations characteristics. Finally, the partial correlation analysis and the partial derivative model were used to analyze the influences and contributions of climate factors on FVC, respectively. The results showed that (1) the subtropical FVC had obvious spatiotemporal heterogeneity; the FVC high-coverage and medium-coverage zones were concentratedly and their combined area accounted for more than 70% of the total study area. (2) The interannual variation in the average subtropical FVC from 2001 to 2018 showed a significant growth trend. (3) In 76.28% of the study area, the regional FVC showed an increasing trend, and the remaining regional FVC showed a decreasing trend. However, the overall fluctuations in the FVC (increasing or decreasing) in the region were relatively stable. (4) The influences of climate factors to the FVC exhibited obvious spatial differences. More than half of all pixels exhibited the influence of the average annual minimum temperature and the annual precipitation had positive on FVC, while the average annual maximum temperature had negative on FVC. (5) The contributions of climate changes to FVC had obvious heterogeneity, and the average annual minimum temperature was the main contribution factor affecting the dynamic variations of FVC.

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Strong controls of daily minimum temperature on the autumn photosynthetic phenology of subtropical vegetation in China

Forest Ecosystems ◽

10.1186/s40663-021-00309-9 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Peixin Ren ◽

Zelin Liu ◽

Xiaolu Zhou ◽

Changhui Peng ◽

Jingfeng Xiao ◽

...

Keyword(s):

Climate Change ◽

Minimum Temperature ◽

Vegetation Index ◽

Climatic Factors ◽

Time Lag ◽

Evergreen Forest ◽

Maximum Temperature ◽

Daily Minimum Temperature ◽

Study Region ◽

Cumulative Precipitation

Abstract Background Vegetation phenology research has largely focused on temperate deciduous forests, thus limiting our understanding of the response of evergreen vegetation to climate change in tropical and subtropical regions. Results Using satellite solar-induced chlorophyll fluorescence (SIF) and MODIS enhanced vegetation index (EVI) data, we applied two methods to evaluate temporal and spatial patterns of the end of the growing season (EGS) in subtropical vegetation in China, and analyze the dependence of EGS on preseason maximum and minimum temperatures as well as cumulative precipitation. Our results indicated that the averaged EGS derived from the SIF and EVI based on the two methods (dynamic threshold method and derivative method) was later than that derived from gross primary productivity (GPP) based on the eddy covariance technique, and the time-lag for EGSsif and EGSevi was approximately 2 weeks and 4 weeks, respectively. We found that EGS was positively correlated with preseason minimum temperature and cumulative precipitation (accounting for more than 73% and 62% of the study areas, respectively), but negatively correlated with preseason maximum temperature (accounting for more than 59% of the study areas). In addition, EGS was more sensitive to the changes in the preseason minimum temperature than to other climatic factors, and an increase in the preseason minimum temperature significantly delayed the EGS in evergreen forests, shrub and grassland. Conclusions Our results indicated that the SIF outperformed traditional vegetation indices in capturing the autumn photosynthetic phenology of evergreen forest in the subtropical region of China. We found that minimum temperature plays a significant role in determining autumn photosynthetic phenology in the study region. These findings contribute to improving our understanding of the response of the EGS to climate change in subtropical vegetation of China, and provide a new perspective for accurately evaluating the role played by evergreen vegetation in the regional carbon budget.

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The effect of average temperature on suicide rates in five urban California counties, 1999–⁠2019: an ecological time series analysis

BMC Public Health ◽

10.1186/s12889-021-11001-6 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Sierra Cheng ◽

Rebecca Plouffe ◽

Stephanie M. Nanos ◽

Mavra Qamar ◽

David N. Fisman ◽

...

Keyword(s):

Public Health ◽

Suicide Rate ◽

Minimum Temperature ◽

The United States ◽

Additive Models ◽

Maximum Temperature ◽

Mortality Data ◽

Average Temperature ◽

Suicide Rates ◽

Average Maximum

Abstract Background Suicide is among the top 10 leading causes of premature morality in the United States and its rates continue to increase. Thus, its prevention has become a salient public health responsibility. Risk factors of suicide transcend the individual and societal level as risk can increase based on climatic variables. The purpose of the present study is to evaluate the association between average temperature and suicide rates in the five most populous counties in California using mortality data from 1999 to 2019. Methods Monthly counts of death by suicide for the five counties of interest were obtained from CDC WONDER. Monthly average, maximum, and minimum temperature were obtained from nCLIMDIV for the same time period. We modelled the association of each temperature variable with suicide rate using negative binomial generalized additive models accounting for the county-specific annual trend and monthly seasonality. Results There were over 38,000 deaths by suicide in California’s five most populous counties between 1999 and 2019. An increase in average temperature of 1 °C corresponded to a 0.82% increase in suicide rate (IRR = 1.0082 per °C; 95% CI = 1.0025–1.0140). Estimated coefficients for maximum temperature (IRR = 1.0069 per °C; 95% CI = 1.0021–1.0117) and minimum temperature (IRR = 1.0088 per °C; 95% CI = 1.0023–1.0153) were similar. Conclusion This study adds to a growing body of evidence supporting a causal effect of elevated temperature on suicide. Further investigation into environmental causes of suicide, as well as the biological and societal contexts mediating these relationships, is critical for the development and implementation of new public health interventions to reduce the incidence of suicide, particularly in the face increasing temperatures due to climate change.

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Effects of Cropland Expansion on Temperature Extremes in Western India from 1982 to 2015

Land ◽

10.3390/land10050489 ◽

2021 ◽

Vol 10 (5) ◽

pp. 489

Author(s):

Jinxiu Liu ◽

Weihao Shen ◽

Yaqian He

Keyword(s):

Land Use ◽

Heat Flux ◽

Land Cover ◽

Minimum Temperature ◽

Negative Impact ◽

Maximum Temperature ◽

Daily Minimum Temperature ◽

Daily Maximum ◽

Temperature Extremes ◽

Western India

India has experienced extensive land cover and land use change (LCLUC). However, there is still limited empirical research regarding the impact of LCLUC on climate extremes in India. Here, we applied statistical methods to assess how cropland expansion has influenced temperature extremes in India from 1982 to 2015 using a new land cover and land use dataset and ECMWF Reanalysis V5 (ERA5) climate data. Our results show that during the last 34 years, croplands in western India increased by ~33.7 percentage points. This cropland expansion shows a significantly negative impact on the maxima of daily maximum temperature (TXx), while its impacts on the maxima of daily minimum temperature and the minima of daily maximum and minimum temperature are limited. It is estimated that if cropland expansion had not taken place in western India over the 1982 to 2015 period, TXx would likely have increased by 0.74 (±0.64) °C. The negative impact of croplands on reducing the TXx extreme is likely due to evaporative cooling from intensified evapotranspiration associated with croplands, resulting in increased latent heat flux and decreased sensible heat flux. This study underscores the important influences of cropland expansion on temperature extremes and can be applicable to other geographic regions experiencing LCLUC.

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