scholarly journals Population Exposure to Compound Droughts and Heatwaves in the Observations and ERA5 Reanalysis Data in the Gan River Basin, China

Land ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1021
Author(s):  
Yuqing Zhang ◽  
Guangxiong Mao ◽  
Changchun Chen ◽  
Liucheng Shen ◽  
Binyu Xiao
Keyword(s):  
River Basin ◽  
Population Change ◽  
Reanalysis Data ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Circulation System ◽  
Population Exposure ◽  
Daily Maximum ◽  
The One ◽  
Background Fields

The frequency, duration, and magnitude of heatwaves and droughts are expected to increase in a warming climate, which can have profound impacts on the environment, society, and public health, and these may be severely affected specifically by compound droughts and heatwaves (CDHWs). On the basis of daily maximum temperature data and the one-month standardized precipitation evapotranspiration index (SPEI) from 1961 to 2018, the Gan River Basin (GRB) was taken as a case here to construct CDHW identification indicators and quantify the population exposure to CDHWs. We found that ERA5 reanalysis data performed well in overall simulating temperature, precipitation, one-month SPEI, heatwaves, and CDHWs in the GRB from 1961 to 2018. CDHWs during the period from 1997 to 2018 were slightly higher than that in 1961–1997. CDHWs were more likely to occur in the southern parts of the basin due to the relatively high values of drought–heatwave dependence indices. Atmospheric circulation analysis of the 2003 CDHW in the GRB showed a relatively long-lasting anomalous high pressure and anticyclonic circulation system, accompanied by the positive convective inhibition and surface net solar radiation anomalies. These circulating background fields eventually led to the exceptional 2003 CDHW occurrence in the GRB. The population exposure to CDHWs basically increased, especially for the moderate CDHWs in ERA5. The change in total exposure was mainly due to climate change. Compared with the period from 1989 to 1998, the contributions of the population change effect in 2009–2018 gradually increased with the increase in the CDHW magnitude both in the observations and ERA5 reanalysis data.

scholarly journals Changes of Extreme Temperature and Its Influencing Factors in Shiyang River Basin, Northwest China

Atmosphere ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1171
Author(s):  
Junju Zhou ◽  
Jumei Huang ◽  
Xi Zhao ◽  
Li Lei ◽  
Wei Shi ◽  
...  
Keyword(s):  
Global Warming ◽  
River Basin ◽  
Minimum Temperature ◽  
Extreme Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Extreme Temperatures ◽  
Shiyang River Basin

The increase in the frequency and intensity of extreme weather events around the world has led to the frequent occurrence of global disasters, which have had serious impacts on the society, economic and ecological environment, especially fragile arid areas. Based on the daily maximum temperature and daily minimum temperature data of four meteorological stations in Shiyang River Basin (SRB) from 1960 to 2015, the spatio-temporal variation characteristics of extreme temperature indices were analyzed by means of univariate linear regression analysis, Mann–Kendall test and correlation analysis. The results showed that the extreme temperatures warming indices and the minimum of daily maximum temperature (TXn) and the minimum of daily minimum temperature (TNn) of cold indices showed an increasing trend from 1960 to 2016, especially since the 1990s, where the growth rate was fast and the response to global warming was sensitive. Except TXn and TNn, other cold indices showed a decreasing trend, especially Diurnal temperature (DTR) range, which decreased rapidly, indicating that the increasing speed of daily min-temperature were greater than of daily max-temperature in SRB. In space, the change tendency rate of the warm index basically showed an obvious altitude gradient effect that decreased with the altitude, which was consistent with Frost day (FD0) and Cool nights (TN10p) in the cold index, while Ice days (ID0) and Cool days (TX10p) are opposite. The mutation of the cold indices occurred earlier than the warm indices, illustrating that the cold indices in SRB were more sensitive to global warming. The change in extreme temperatures that would have a significant impact on the vegetation and glacier permafrost in the basin was the result of the combined function of different atmospheric circulation systems, which included the Arctic polar vortex, Western Pacific subtropical high and Qinghai-tibet Plateau circulation.

scholarly journals Attributing trends in extremely hot days to changes in atmospheric dynamics

2015 ◽  
Vol 3 (5) ◽  
pp. 3323-3367
Author(s):  
J. A. García-Valero ◽  
J. P. Montávez ◽  
J. J. Gómez-Navarro ◽  
P. Jiménez-Guerrero
Keyword(s):  
Large Scale ◽  
Atmospheric Dynamics ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Sea Level Pressure ◽  
Circulation Types ◽  
Hot Days ◽  
The One ◽  
Atmospheric Variables

Abstract. This paper proposes a method that allows the detection of trends in the frequency of extreme events and its attribution to changes in atmospheric dynamics characterized through Circulation Types (CTs). The method is applied to summer Extremely Hot Days (EHD) in Spain during the period 1958–2008. For carrying out this exercise, regional series of daily maximum temperature are derived from the regional dataset Spain02. Eight regions with different daily maximum temperature variability are identified. All of them exhibit important trends in the occurrence of EHDs, especially in inner regions. Links between the probability of EHD occurrence in the regions and CTs have been calculated. Furthermore, the consistency of the results to the atmospheric variables used in defining the CTs is analyzed. Sea Level Pressure (SLP), Temperature at 850 hPa Level (T850) and Geopotential Height at 500 hPa Level (Z500) from the ERA40 dataset have been used for the six CT classifications obtained using the variables separately and in different combinations of pairs. The optimum choice of large scale variables depends on the region under consideration, being the combination SLP-T850 the one giving the most suitable characterization for most of them. Finally, an attribution exercise of the regional EHD trends to the dynamics is proposed. Results show that the maximum of attributable EHD trends to changes in dynamics in every region is always below 5 %, being even lower than 20% in those regions with the largest EHD trends, mainly located in the center of the Iberian Peninsula (IP).

scholarly journals Late‐July Barrier for Subseasonal Forecast of Summer Daily Maximum Temperature Over Yangtze River Basin

2018 ◽  
Vol 45 (22) ◽  
pp. 12,610-12,615 ◽  
Author(s):  
Jing Yang ◽  
Tao Zhu ◽  
Miaoni Gao ◽  
Hai Lin ◽  
Bin Wang ◽  
...  
Keyword(s):  
River Basin ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum

scholarly journals SURFACE OZONE CONCENTRATIONS AND THE METEOROLOGICAL CONDITIONS AT AN URBAN TROPICAL SITE IN THE SOUTHERN HEMISPHERE

2014 ◽  
Vol 32 (3) ◽  
pp. 383
Author(s):  
Abel Antônio Silva
Keyword(s):  
Cloud Cover ◽  
Surface Ozone ◽  
Meteorological Condition ◽  
Meteorological Conditions ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Late Winter ◽  
Daily Maximum ◽  
Anthropogenic Pollutants ◽  
The One

ABSTRACT. Surface ozone plays a key role in the photochemistry of the low troposphere being associated with health and environmental problems. It is formed froma pool of reactions involving natural and anthropogenic pollutants, solar radiation, and the meteorological condition. In this study, 12-months of recent measurementsof surface ozone concentration (SOC) are presented for an urban tropical site (19.92◦S, 43.94◦W, 858 m asl, 331 km2) in Brazil. An analysis of the SOC dependenceon the meteorological conditions (cloud cover, wind direction and speed, number of rainy days, precipitation, humidity, and daily maximum temperature) is introduced.The daily maxima of the one-hour averaged data of SOC (1-h SOC) ranged from 8.7 to 96.1 parts-per-billion by volume (ppbv) and averaged 38.1 ± 13.7 ppbv (1σ),while the maxima of the monthly averages of the 1-h SOC varied from 24.5 ±8.8 ppbv in early fall to 46.7± 9.3 ppbv in late winter. Monthly averages of 1-h SOC andhumidity showed fair linearity among the meteorological parameters investigated. In addition, the cloud cover in summer seems to affect SOC the most.Keywords: ozone, clouds, meteorology.RESUMO. O ozônio de superfície desempenha um importante papel na fotoquímica da baixa troposfera, estando associado a questões ambientais e de saúde. Ele é formado a partir de um grupo de reações envolvendo fontes naturais e antropogênicas de poluentes, radiação solar e condições meteorológicas. Neste trabalho, 12 meses de medidas recentes da concentração de ozônio de superfície (COS) são apresentadas para uma localidade urbana tropical (19,92◦S, 43,94◦O, 858 m anm, 331 km2) no Brasil. Uma análise da dependência da COS com as condições meteorológicas (cobertura de nuvens, direção e velocidade dos ventos, número de dias chuvosos, precipitação, umidade e temperatura máxima diária) é introduzida. As máximas diárias da média horária de COS (1-h COS) variaram de 8,7 a 96,1 partes por bilhão em volume (ppbv) com média de 38,1±13,7 ppbv (1σ), enquanto as máximas das médias mensais de 1-h COS variaram de 24,5±8,8 ppbv no início do outono a 46,7±9,3 ppbv no final da primavera. As médias mensais de 1-h COS e umidade apresentaram uma linearidade razoável dentre os parâmetros meteorológicos investigados. Além disso, a cobertura de nuvens no verão parece ter afetado de forma mais intensa a COS.Palavras-chave: ozônio, nuvens, meteorologia.

scholarly journals Two-Meter Temperature and Precipitation from Atmospheric Reanalysis Evaluated for Alaska

2016 ◽  
Vol 55 (4) ◽  
pp. 901-922 ◽  
Author(s):  
Rick Lader ◽  
Uma S. Bhatt ◽  
John E. Walsh ◽  
T. Scott Rupp ◽  
Peter A. Bieniek
Keyword(s):  
Global Climate ◽  
Weather Forecast ◽  
Heavy Precipitation ◽  
Reanalysis Data ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Monthly Data ◽  
Temperature And Precipitation ◽  
Grid Points

AbstractAlaska is experiencing effects of global climate change that are due, in large part, to the positive feedback mechanisms associated with polar amplification. The major risk factors include loss of sea ice and glaciers, thawing permafrost, increased wildfires, and ocean acidification. Reanalyses, integral to understanding mechanisms of Alaska’s past climate and to helping to calibrate modeling efforts, are based on the output of weather forecast models that assimilate observations. This study evaluates temperature and precipitation from five reanalyses at monthly and daily time scales for the period 1979–2009. Monthly data are evaluated spatially at grid points and for six climate zones in Alaska. In addition, daily maximum temperature, minimum temperature, and precipitation from reanalyses are compared with meteorological-station data at six locations. The reanalyses evaluated in this study include the NCEP–NCAR reanalysis (R1), North American Regional Reanalysis (NARR), Climate Forecast System Reanalysis (CFSR), ERA-Interim, and the Modern-Era Retrospective Analysis for Research and Applications (MERRA). Maps of seasonal bias and standard deviation, constructed from monthly data, show how the reanalyses agree with observations spatially. Cross correlations between the monthly gridded and daily station time series are computed to provide a measure of confidence that data users can assume when selecting reanalysis data in a region without many surface observations. A review of natural hazards in Alaska indicates that MERRA is the top reanalysis for wildfire and interior-flooding applications. CFSR is the recommended reanalysis for North Slope coastal erosion issues and, along with ERA-Interim, for heavy precipitation in southeastern Alaska.

scholarly journals Return levels of temperature extremes in southern Pakistan

2017 ◽  
Vol 8 (4) ◽  
pp. 1263-1278 ◽  
Author(s):  
Maida Zahid ◽  
Richard Blender ◽  
Valerio Lucarini ◽  
Maria Caterina Bramati
Keyword(s):  
Reanalysis Data ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Temperature Extremes ◽  
Extreme Temperatures ◽  
Peaks Over Threshold ◽  
Return Levels ◽  
Rural And Urban ◽  
The World

Abstract. Southern Pakistan (Sindh) is one of the hottest regions in the world and is highly vulnerable to temperature extremes. In order to improve rural and urban planning, it is useful to gather information about the recurrence of temperature extremes. In this work, return levels of the daily maximum temperature Tmax are estimated, as well as the daily maximum wet-bulb temperature TWmax extremes. We adopt the peaks over threshold (POT) method, which has not yet been used for similar studies in this region. Two main datasets are analyzed: temperatures observed at nine meteorological stations in southern Pakistan from 1980 to 2013, and the ERA-Interim (ECMWF reanalysis) data for the nearest corresponding locations. The analysis provides the 2-, 5-, 10-, 25-, 50-, and 100-year return levels (RLs) of temperature extremes. The 90 % quantile is found to be a suitable threshold for all stations. We find that the RLs of the observed Tmax are above 50 °C at northern stations and above 45 °C at the southern stations. The RLs of the observed TWmax exceed 35 °C in the region, which is considered as a limit of survivability. The RLs estimated from the ERA-Interim data are lower by 3 to 5 °C than the RLs assessed for the nine meteorological stations. A simple bias correction applied to ERA-Interim data improves the RLs remarkably, yet discrepancies are still present. The results have potential implications for the risk assessment of extreme temperatures in Sindh.

scholarly journals Climate Changes and Associated Multiscale Impacts on Watershed Discharge over the Upper Reach of Yarlung Zangbo River Basin, China

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jinping Liu ◽  
Wanchang Zhang
Keyword(s):  
River Basin ◽  
Time Scales ◽  
Climate Changes ◽  
Ensemble Empirical Mode Decomposition ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Alpine Regions ◽  
Yarlung Zangbo River ◽  
Different Time Scales

Watershed discharge (WD) in the alpine regions, such as the upper reach of Yarlung Zangbo River Basin (YZRB), China, could have changed severely in response to climate changes. Yet, how hydrometeorological variables varied at different time scales and how WD varied in response to hydrometeorological variables in the alpine regions remained questions to be answered. The ensemble empirical mode decomposition (EEMD) method was employed in this study to investigate the nonlinear climate change trends (averaged and extreme states) and the associated multiscale impacts on WD variations over the upper reach of the YZRB during 1961–2009. All investigated hydroclimatic variables, i.e., precipitation, temperature, and WD, were found to be varied nonlinearly with clear multiscale oscillations characterizing great differences in the oscillation periods, corresponding significance levels, and variance contribution rates, among which precipitation posed a weak impact on WD variations, while temperature played a significant role in WD fluctuations. Furthermore, among all temperature extremes, the dominant index affecting WD variations was TXm (annual mean of the daily maximum temperature) but not TXx (annual maximum of the daily maximum temperature) at both interannual and interdecadal scales, which might be caused by that TXx increased evapotranspiration and reduced WD. A significant correlation between temperature (both averaged and partial extreme states) and annual WD at both interannual and interdecadal scales indicated that a synchronous change existed between them. The present study provided first insight into how hydrometeorological variables varied at different time scales and how WD fluctuated in response to hydrometeorological variables over the upper reach of the YZRB, China.

scholarly journals Statistical analysis of extreme weather events in the Diyala River basin, Iraq

2021 ◽  
Author(s):  
Noor M. Naqi ◽  
Monim H. Al-Jiboori ◽  
Abdul-Sahib T. Al-Madhhachi
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Extreme Events ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Positive Temperature ◽  
Climate Extreme ◽  
Weather Events ◽  
Diyala River

Abstract Extreme climate and weather events have direct impacts on human life, the environment, and resources. The Diyala River basin is shared between Iraq and Iran, which makes it vulnerable not only to climate change effects but also to upstream control. Therefore, understanding and predicting extreme events is an essential step to help decision-makers make proactive plans to reduce expected damages. The pattern of extreme events has been identified using climate extreme indices developed by the World Meteorological Organization and Expert Team on Climate Change Detection Indices using ClimPACT2 software. Data were obtained from three meteorological stations in Iraq (Sulaymania, Khanakin, and Baghdad) and one in Iran (Sanandaj) over a period of 20 years (2000–2020). Results for temperature showed seven statistically significant positive trends for only three indices (annual number of days with daily maximum temperature of >35°, difference between daily maximum and daily minimum temperatures, and percentage of days with maximum temperature of >90th percentile, indicating an increase in that temperature). Baghdad station had positive temperature trends for all indices. Trends for precipitation were nearly all nonsignificant and difficult to anticipate compared with those for temperature. Percentile-based indices showed more dry and warm events than wet and cold.

scholarly journals Social media reveal ecoregional variation in how weather influences visitor behavior in U.S. National Park Service units

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emily J. Wilkins ◽  
Peter D. Howe ◽  
Jordan W. Smith
Keyword(s):  
National Park ◽  
National Park Service ◽  
Spatial Behavior ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Daily Weather ◽  
Visitor Behavior ◽  
Park Service ◽  
The Impact

AbstractDaily weather affects total visitation to parks and protected areas, as well as visitors’ experiences. However, it is unknown if and how visitors change their spatial behavior within a park due to daily weather conditions. We investigated the impact of daily maximum temperature and precipitation on summer visitation patterns within 110 U.S. National Park Service units. We connected 489,061 geotagged Flickr photos to daily weather, as well as visitors’ elevation and distance to amenities (i.e., roads, waterbodies, parking areas, and buildings). We compared visitor behavior on cold, average, and hot days, and on days with precipitation compared to days without precipitation, across fourteen ecoregions within the continental U.S. Our results suggest daily weather impacts where visitors go within parks, and the effect of weather differs substantially by ecoregion. In most ecoregions, visitors stayed closer to infrastructure on rainy days. Temperature also affects visitors’ spatial behavior within parks, but there was not a consistent trend across ecoregions. Importantly, parks in some ecoregions contain more microclimates than others, which may allow visitors to adapt to unfavorable conditions. These findings suggest visitors’ spatial behavior in parks may change in the future due to the increasing frequency of hot summer days.

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