scholarly journals Global Heat Wave Hazard Considering Humidity Effects during the 21st Century

2019 ◽  
Vol 16 (9) ◽  
pp. 1513 ◽  
Author(s):  
Xi Chen ◽  
Ning Li ◽  
Jiawei Liu ◽  
Zhengtao Zhang ◽  
Yuan Liu
Keyword(s):  
Relative Humidity ◽  
Heat Wave ◽  
Air Temperature ◽  
Greenhouse Gas Emission ◽  
Heat Waves ◽  
Surface Air Temperature ◽  
Heat Index ◽  
Humidity Effects ◽  
The Difference ◽  
Heat Hazard

Humidity is a significant factor contributing to heat stress, but without enough consideration in studies of quantifying heat hazard or heat risk assessment. Here, the simplified wet-bulb globe temperature (WBGT) considering joint effects of temperature and humidity was utilized as a heat index and the number of annual total heat wave days (HWDs) was employed to quantify heat hazard. In order to evaluate the humidity effects on heat waves, we quantified the difference in the number of HWDs over global land based on air temperature and WBGT. Spatial and temporal changes in surface air temperature, relative humidity, WBGT, and the difference in HWDs were analyzed using multi-model simulations for the reference period (1986–2005) and different greenhouse gas emission scenarios. Our analysis suggests that annual mean WBGT has been increasing since 1986, which is consistent with the rising trend in surface air temperature despite a slight decrease in relative humidity. Additionally, changes in annual mean WBGT are smaller and more spatially uniform than those in annual mean air temperature as a cancelation effect between temperature and water vapor. Results show that there is an underestimation of around 40–140 days in the number of HWDs per year in most regions within 15° latitude of the equator (the humid and warm tropics) during 2076–2095 without considering humidity effects. However, the estimation of HWDs has limited distinction between using WBGT and temperature alone in arid or cold regions.

scholarly journals Non-Stationary Frequency Analysis and Uncertainty of Heat Wave Events

2021 ◽  
Vol 21 (1) ◽  
pp. 301-310
Author(s):  
Jiyu Seo ◽  
Jeongeun Won ◽  
Jeonghyeon Choi ◽  
Okjeong Lee ◽  
Sangdan Kim
Keyword(s):  
Public Health ◽  
Climate Change ◽  
Global Warming ◽  
Energy Management ◽  
Heat Wave ◽  
Air Temperature ◽  
Frequency Analysis ◽  
Heat Waves ◽  
Surface Air Temperature ◽  
Return Periods

Due to global warming, there is an increasing concern regarding persistent and severe heat waves. The maximum daily surface air temperature observations show strong non-stationary features, and the increased intensity and persistence of heat wave events have been observed in many regions. The heat wave persistence day frequency (HPF) curve, which correlates the intensity of a heat wave persistence event for days with return periods, can be a useful tool to analyze the frequency of heat wave events. In this study, non-stationary HPF curves are developed to explain the trend in the increase of the surface air temperature due to climate change, and their uncertainty is analyzed. The non-stationary HPF model can be used in climate change adaptation management such as public health, public safety, and energy management.

scholarly journals Retrospection of Heatwave and Heat Index: A Case Study using ERA5 Dataset

2021 ◽  
Author(s):  
Amit Awasthi ◽  
Kirti Vishwakarma ◽  
Kanhu Charan Pattnayak
Keyword(s):  
Relative Humidity ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Surface Air Temperature ◽  
Climatic Conditions ◽  
Heat Index ◽  
The World ◽  
Definition Of ◽  
Different Parts

Abstract The frequency and intensity of extreme events especially Heat Waves (HW) are growing all around the world which ultimately poses a serious threat to the health of individuals. To quantify the effects of extreme temperature, appropriate information, and the importance of HW and Heat Index (HI) are carefully discussed for different parts of the world. Varied definitions of the HW and HI formula proposed and used by different countries are carried out systematically continent-wise. Different studies highlighted the number of definitions of HW, however mostly used Steadman’s formulae for the calculation of HI that uses surface air temperature and relative humidity as climatic fields which was developed in the late 1970s. Since then, dramatic changes in climatic conditions have been observed as evident from the ERA5 datasets which need to be addressed. Likewise, the definition of HW, which is modified by the researchers as per the geographic conditions, necessary modification in Steadman’s equation also needs to be done. This study will help the researcher community to understand the importance of HW and HI and think about its modification which further helps in better adaptation and application. Furthermore, it opens the scope to develop an equation based on the present scenario keeping in mind the basics of an index as considered by Steadman.

scholarly journals Retrospection of heatwave and heat index

2021 ◽  
Author(s):  
Amit Awasthi ◽  
Kirti Vishwakarma ◽  
Kanhu Charan Pattnayak
Keyword(s):  
Relative Humidity ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Surface Air Temperature ◽  
Climatic Conditions ◽  
Heat Index ◽  
Threefold Increase ◽  
The World ◽  
Definition Of ◽  
Different Parts

AbstractThe frequency and intensity of extreme events especially heat waves (HW) are growing all around the world which ultimately poses a serious threat to the health of individuals. To quantify the effects of extreme temperature, appropriate information, and the importance of HW and heat index (HI) are carefully discussed for different parts of the world. Varied definitions of the HW and HI formula proposed and used by different countries are carried out systematically continent-wise. Different studies highlighted the number of definitions of HW; however, mostly used Steadman’s formulae, which was developed in the late 1970s, for the calculation of HI that uses surface air temperature and relative humidity as climatic fields. Since then, dramatic changes in climatic conditions have been observed as evident from the ERA5 datasets which need to be addressed; likewise, the definition of HW, which is modified by the researchers as per the geographic conditions. It is evident from the ERA5 data that the temperature has increased by 1–2 °C as compared to the 1980s. There is a threefold increase in the number of heatwave days over most of the continents in the last 40 years. This study will help the researcher community to understand the importance of HW and HI. Furthermore, it opens the scope to develop an equation based on the present scenario keeping in mind the basics of an index as considered by Steadman.

scholarly journals Effects of trees, gardens, and nature trails on heat index and child health: design and methods of the Green Schoolyards Project

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kevin Lanza ◽  
Melody Alcazar ◽  
Deanna M. Hoelscher ◽  
Harold W. Kohl
Keyword(s):  
Physical Activity ◽  
United States ◽  
Relative Humidity ◽  
Air Temperature ◽  
The United States ◽  
Heat Index ◽  
Activity Levels ◽  
Natural Setting ◽  
Physical Activity Levels ◽  
Nature Trails

Abstract Background Latinx children in the United States are at high risk for nature-deficit disorder, heat-related illness, and physical inactivity. We developed the Green Schoolyards Project to investigate how green features—trees, gardens, and nature trails—in school parks impact heat index (i.e., air temperature and relative humidity) within parks, and physical activity levels and socioemotional well-being of these children. Herein, we present novel methods for a) observing children’s interaction with green features and b) measuring heat index and children’s behaviors in a natural setting, and a selection of baseline results. Methods During two September weeks (high temperature) and one November week (moderate temperature) in 2019, we examined three joint-use elementary school parks in Central Texas, United States, serving predominantly low-income Latinx families. To develop thermal profiles for each park, we installed 10 air temperature/relative humidity sensors per park, selecting sites based on land cover, land use, and even spatial coverage. We measured green features within a geographic information system. In a cross-sectional study, we used an adapted version of System for Observing Play and Recreation in Communities (SOPARC) to assess children’s physical activity levels and interactions with green features. In a cohort study, we equipped 30 3rd and 30 4th grade students per school during recess with accelerometers and Global Positioning System devices, and surveyed these students regarding their connection to nature. Baseline analyses included inverse distance weighting for thermal profiles and summing observed counts of children interacting with trees. Results In September 2019, average daily heat index ranged 2.0 °F among park sites, and maximum daily heat index ranged from 103.4 °F (air temperature = 33.8 °C; relative humidity = 55.2%) under tree canopy to 114.1 °F (air temperature = 37.9 °C; relative humidity = 45.2%) on an unshaded playground. 10.8% more girls and 25.4% more boys interacted with trees in September than in November. Conclusions We found extreme heat conditions at select sites within parks, and children positioning themselves under trees during periods of high heat index. These methods can be used by public health researchers and practitioners to inform the redesign of greenspaces in the face of climate change and health inequities.

scholarly journals Recent atmospheric changes and future projections along the Saudi Arabian Red Sea Coast

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Abdulhakim Bawadekji ◽  
Kareem Tonbol ◽  
Nejib Ghazouani ◽  
Nidhal Becheikh ◽  
Mohamed Shaltout
Keyword(s):  
Relative Humidity ◽  
Sea Level ◽  
Air Temperature ◽  
Surface Wind ◽  
Surface Air Temperature ◽  
Saudi Arabian ◽  
Sea Level Pressure ◽  
Ensemble Mean ◽  
Red Sea Coast ◽  
Sea Coast

AbstractRecent and future climate diagrams (surface air temperature, surface relative humidity, surface wind, and mean sea level pressure) for the Saudi Arabian Red Sea Coast are analysed based on hourly observations (2016–2020) and hourly ERA5 data (1979–2020) with daily GFDL mini-ensemble means (2006–2100). Moreover, GFDL mini-ensemble means are calculated based on the results of three GFDL simulations (GFDL-CM3, GFDL-ESM2M, and GFDL-ESM2G). Observation data are employed to describe the short-term current weather variability. However, ERA5 data are considered to study the long-term current weather variability after bias removal via a comparison to observations. Finally, a bias correction statistical model was developed by matching the cumulative distribution functions (CDFs) of corrected ERA5 and mini-ensemble mean data over 15 years (2006–2020). The obtained local statistic were used to statically downscale GFDL mini-ensemble means to study the future uncertainty in the atmospheric parameters studied. There occurred significant spatial variability across the study area, especially regarding the surface air temperature and relative humidity, based on monthly analysis of both observation and ERA5 data. Moreover, the results indicated that the ERA5 data suitably describe Tabuk, Jeddah and Jizan weather conditions with a marked spatial variability. The best performance of ERA5 surface air temperature and relative humidity (surface wind speed and sea level pressure) data was detected in Tabuk (Jeddah). These data for the Saudi Arabian Red Sea coast, 1979–2020, exhibit significant positive trends of the surface air temperature and surface wind speed and significant negative trends of the relative humidity and sea level pressure. The GFDL mini-ensemble mean projection result, up to 2100, contains a significant bias in the studied weather parameters. This is partly attributed to the coarse GFDL resolution (2° × 2°). After bias removal, the statistically downscaled simulations based on the GFDL mini-ensemble mean indicate that the climate in the study area will experience significant changes with a large range of uncertainty according to the considered scenario and regional variations.

scholarly journals Influence of Below-Cloud Evaporation on Deuterium Excess in Precipitation of Arid Central Asia and Its Meteorological Controls

2016 ◽  
Vol 17 (7) ◽  
pp. 1973-1984 ◽  
Author(s):  
Shengjie Wang ◽  
Mingjun Zhang ◽  
Yanjun Che ◽  
Xiaofan Zhu ◽  
Xuemei Liu
Keyword(s):  
Relative Humidity ◽  
Central Asia ◽  
Air Temperature ◽  
Sampling Site ◽  
Heavy Precipitation ◽  
Cloud Base ◽  
Deuterium Excess ◽  
Arid Central Asia ◽  
Observation Network ◽  
The Difference

Abstract The deuterium excess is a second-order parameter linking water-stable oxygen and hydrogen isotopes and has been widely used in hydrological studies. The deuterium excess in precipitation is greatly influenced by below-cloud evaporation through unsaturated air, especially in an arid climate. Based on an observation network of isotopes in precipitation of arid central Asia, the difference in deuterium excess from cloud base to ground was calculated for each sampling site. The difference on the southern slope of the Tian Shan is generally larger than that on the northern slope, and the difference during the summer months is greater than that during the winter months. Generally, an increase of 1% in evaporation of raindrops causes deuterium excess to decrease by approximately 1‰. Under conditions of low air temperature, high relative humidity, heavy precipitation, and large raindrop diameter, a good linear correlation is exhibited between evaporation proportion and difference in deuterium excess, and a linear regression slope of <1‰ %−1 can be seen; in contrast, under conditions of high air temperature, low relative humidity, light precipitation, and small raindrop diameter, the linear relationship is relatively weak, and the slope is much larger than 1‰ %−1. A sensitivity analysis under different climate scenarios indicates that, if air temperature has increased by 5°C, deuterium excess difference decreases by 0.3‰–4.0‰ for each site; if relative humidity increases by 10%, deuterium excess difference increases by 1.1‰–10.3‰.

Can climate adaptation solutions fix the urban heat island? An assessment of the thermal conditions during heat waves in Vienna impacted by climate change and urban development scenarios for the mid-21st-century

2020 ◽  
Author(s):  
Paul Hamer ◽  
Heidelinde Trimmel ◽  
Philipp Weihs ◽  
Stéphanie Faroux ◽  
Herbert Formayer ◽  
...  
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Heat Wave ◽  
Air Temperature ◽  
Urban Areas ◽  
Climate Adaptation ◽  
Heat Waves ◽  
Heat Island ◽  
Human Thermal Comfort ◽  
Urban Heat

<p>Climate change threatens to exacerbate existing problems in urban areas arising from the urban heat island. Furthermore, expansion of urban areas and rising urban populations will increase the numbers of people exposed to hazards in these vulnerable areas. We therefore urgently need study of these environments and in-depth assessment of potential climate adaptation measures.</p><p>We present a study of heat wave impacts across the urban landscape of Vienna for different future development pathways and for both present and future climatic conditions. We have created two different urban development scenarios that estimate potential urban sprawl and optimized development concerning future building construction in Vienna and have built a digital representation of each within the Town Energy Balance (TEB) urban surface model. In addition, we select two heat waves of similar frequency of return representative for present and future conditions (following the RCP8.5 scenario) of the mid 21<sup>st</sup> century and use the Weather Research and Forecasting Model (WRF) to simulate both heat wave events. We then couple the two representations urban Vienna in TEB with the WRF heat wave simulations to estimate air temperature, surface temperatures and human thermal comfort during the heat waves. We then identify and apply a set of adaptation measures within TEB to try to identify potential solutions to the problems associated with the urban heat island.</p><p>Global and regional climate change under the RCP8.5 scenario causes the future heat wave to be more severe showing an increase of daily maximum air temperature in Vienna by 7 K; the daily minimum air temperature will increase by 2-4 K. We find that changes caused by urban growth or densification mainly affect air temperature and human thermal comfort local to where new urbanisation takes place and does not occur significantly in the existing central districts.</p><p>Exploring adaptation solutions, we find that a combination of near zero-energy standards and increasing albedo of building materials on the city scale accomplishes a maximum reduction of urban canyon temperature of 0.9 K for the minima and 0.2 K for the maxima. Local scale changes of different adaption measures show that insulation of buildings alone increases the maximum wall surface temperatures by more than 10 K or the maximum mean radiant temperature (MRT) in the canyon by 5 K.  Therefore, additional adaptation to reduce MRT within the urban canyons like tree shade are needed to complement the proposed measures.</p><p>This study concludes that the rising air temperatures expected by climate change puts an unprecedented heat burden on Viennese inhabitants, which cannot easily be reduced by measures concerning buildings within the city itself. Additionally, measures such as planting trees to provide shade, regional water sensitive planning and global reduction of greenhouse gas emissions in order to reduce temperature extremes are required.</p><p>We are now actively seeking to apply this set of tools to a wider set of cases in order to try to find effective solutions to projected warming resulting from climate change in urban areas.</p>

Subseasonal Forecast of Surface Air Temperature Using Superensemble Approaches: Experiments over Northeast Asia for 2018

2021 ◽  
Vol 36 (1) ◽  
pp. 39-51
Author(s):  
Shoupeng Zhu ◽  
Xiefei Zhi ◽  
Fei Ge ◽  
Yi Fan ◽  
Ling Zhang ◽  
...  
Keyword(s):  
Air Temperature ◽  
Lead Time ◽  
Weather Forecasting ◽  
Heat Waves ◽  
Northeast Asia ◽  
Surface Air Temperature ◽  
Poor Quality ◽  
Spatiotemporal Patterns ◽  
Lead Times ◽  
Ensemble Mean

AbstractBridging the gap between weather forecasting and climate prediction, subseasonal to seasonal (S2S) forecasts are of great importance yet currently of relatively poor quality. Using the S2S Prediction Project database, the study evaluates products derived from four operational centers of CMA, KMA, NCEP, and UKMO, and superensemble experiments including the straightforward ensemble mean (EMN), bias-removed ensemble mean (BREM), error-based superensemble (ESUP), and Kalman filter superensemble (KF), in forecasts of surface air temperature with lead times of 6–30 days over northeast Asia in 2018. Validations after the preprocessing of a 5-day running mean suggest that the KMA model shows the highest skill for either the control run or the ensemble mean. The nonequal weighted ESUP is slightly superior to BREM, whereas they both show larger biases than EMN after a lead time of 22 days. The KF forecast constantly outperforms the others, decreasing mean absolute errors by 0.2°–0.5°C relative to EMN. Forecast experiments of the 2018 northeast Asia heat wave reveal that the superensembles remarkably improve the raw forecasts featuring biases of >4°C. The prominent advancement of KF is further confirmed, showing the regionally averaged bias of ≤2°C and the hit rate of 2°C reaching up to 60% at a lead time of 22 days. The superensemble techniques, particularly the KF method of dynamically adjusting the weights in accordance with the latest information available, are capable of improving forecasts of spatiotemporal patterns of surface air temperature on the subseasonal time scale, which could extend the skillful prediction lead time of extreme events such as heat waves to about 3 weeks.

scholarly journals Sensitivity of Precipitation Phase over the Swiss Alps to Different Meteorological Variables

2014 ◽  
Vol 15 (2) ◽  
pp. 685-696 ◽  
Author(s):  
S. Froidurot ◽  
I. Zin ◽  
B. Hingray ◽  
A. Gautheron
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Meteorological Data ◽  
Explanatory Power ◽  
Surface Air Temperature ◽  
Ground Level ◽  
Swiss Alps ◽  
Meteorological Variables ◽  
Study Region ◽  
Precipitation Phase

Abstract In most meteorological or hydrological models, the distinction between snow and rain is based only on a given air temperature. However, other factors such as air moisture can be used to better distinguish between the two phases. In this study, a number of models using different combinations of meteorological variables are tested to determine their pertinence for the discrimination of precipitation phases. Spatial robustness is also evaluated. Thirty years (1981–2010) of Swiss meteorological data are used, consisting of radio soundings from Payerne as well as present weather observations and surface measurements (mean hourly surface air temperature, mean hourly relative humidity, and hourly precipitation) from 14 stations, including Payerne. It appeared that, unlike surface variables, variables derived from the atmospheric profiles (e.g., the vertical temperature gradient) hardly improve the discrimination of precipitation phase at ground level. Among all tested variables, surface air temperature and relative humidity show the greatest explanatory power. The statistical model using these two variables and calibrated for the case study region provides good spatial robustness over the region. Its parameters appear to confirm those defined in the model presented by Koistinen and Saltikoff.

scholarly journals The accuracy of the heat index to explain the excess of mortality and morbidity during heat waves – a case study in a mediterranean climate

2013 ◽  
Vol 20 (20) ◽  
pp. 71-84 ◽  
Author(s):  
Ana Monteiro ◽  
Vânia Carvalho ◽  
Sara Velho ◽  
Carlos Sousa
Keyword(s):  
Heat Wave ◽  
Respiratory Diseases ◽  
Heat Waves ◽  
Heat Index ◽  
Respiratory Morbidity ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Mortality And Morbidity ◽  
Comfort Index ◽  
T Distribution

Abstract The aim of this contribution was to evaluate the accuracy of a well known human comfort index, the heat index, to anticipate the effects of the July 2006 heat wave in mortality (all causes) and morbidity (all causes, respiratory and circulatory disease). Our assessment was done to all citizens, to people of the 75+ cohort and to each gender, in Porto. For further statistical analysis, we calculated an expected number of admissions by averaging the admissions recorded during the comparison period. The 95% confidence interval was calculated, using a standard method based on the t-distribution, for differences between independent means with different population variances, using the Leveane test to evaluate the variance’s homogeneity. During the 2006 heat wave, a 52% mortality excess was registered relatively to the expected mortality (p < 0.001), for all cohorts of the population. The admissions excess for all ages included the admissions due to respiratory diseases (p < 0.029), pneumonia (p < 0.001) and chronic obstructive pulmonary disease (p < 0.001). For the 75+ cohort, the admissions due to respiratory diseases (p < 0.017), pneumonia (p < 0.001) and heart failure (p < 0.610) were also statistically high. The obtained results confirm that the heat index is a truthful method to anticipate the negative impacts of heat waves in human health even in climate contexts adapted to hot summers like at Porto - a Mediterranean tempered climate. The impacts of July 2006’s heat wave in the increase of mortality (all causes) and in respiratory morbidity (all population and 75+cohort) was evident.

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