Sensitivity of warm-sector heavy precipitation to the impact of anthropogenic heating in South China

Previous studies have mostly focused on the effect of anthropogenic heating（AH） on air pollution events. However, few studies have investigated the impact of AH on the warm-sector precipitation over South China. By using the Weather Research and Forecasting model（WRF）coupled with an urban canopy model with appropriate AH release values, the warm-sector heavy rainfall event that occurred over the Pearl River Delta（PRD） during 8 May 2014 was investigated.The results show that the warm-sector precipitation of the PRD is sensitive to the impact of AH.By affecting the convection in the initiation of precipitation, AH can reduce the total precipitation of urban areas by approximately 10%. The possible mechanism by which AH influences the warm-sector heavy precipitation is described as follows： AH induced local convergence shifts towards the border of the PRD and intensified the convection and precipitation therein, by rearranging the thermal distributions of the flow field. In addition, AH changed the local convergence within the urban PRD areas, which was weakened by the homogenous urban thermal environment, and thereby decreased the total urban precipitation.

Impact of Anthropogenic Heat Release on Regional Climate in Three Vast Urban Agglomerations in China

We simulated the impact of anthropogenic heat release （AHR） on the regional climate in three vast city agglomerations in China using the Weather Research and Forecasting model with nested high-resolution modeling.Based on energy consumption and high-quality land use data,we designed two scenarios to represent no-AHR and current-AHR conditions.By comparing the results of the two numerical experiments,changes of surface air temperature and precipitation due to AHR were quantified and analyzed.We concluded that AHR increases the temperature in these urbanized areas by about 0.5℃-1℃,and this increase is more pronounced in winter than in other seasons.The inclusion of AHR enhances the convergence of water vapor over urbanized areas.Together with the warming of the lower troposphere and the enhancement of ascending motions caused by AHR,the average convective available potential energy in urbanized areas is increased.Rainfall amounts in summer over urbanized areas are likely to increase and regional precipitation patterns to be altered to some extent.

Increases in Anthropogenic Heat Release from Energy Consumption Lead to More Frequent Extreme Heat Events in Urban Cities

With economic development and rapid urbanization,increases in Gross Domestic Product and population in fastgrowing cities since the turn of the 21st Century have led to increases in energy consumption.Anthropogenic heat flux released to the near-surface atmosphere has led to changes in urban thermal environments and severe extreme temperature events.To investigate the effects of energy consumption on urban extreme temperature events,including extreme heat and cold events,a dynamic representation scheme of anthropogenic heat release(AHR)was implemented in the Advanced Research version of the Weather Research and Forecasting(WRF)model,and AHR data were developed based on energy consumption and population density in a case study of Beijing,China.Two simulations during 1999−2017 were then conducted using the developed WRF model with 3-km resolution with and without the AHR scheme.It was shown that the mean temperature increased with the increase in AHR,and more frequent extreme heat events were produced,with an annual increase of 0.02−0.19 days,as well as less frequent extreme cold events,with an annual decrease of 0.26−0.56 days,based on seven extreme temperature indices in the city center.AHR increased the sensible heat flux and led to surface energy budget changes,strengthening the dynamic processes in the atmospheric boundary layer that reduce AHR heating efficiency more in summer than in winter.In addition,it was concluded that suitable energy management might help to mitigate the impact of extreme temperature events in different seasons.

Spatiotemporal Variations and Controls on Anthropogenic Heat Fluxes in 12 Selected Cities in the Eastern China

Spatiotemporal variations of anthropogenic heat flux(AHF)is reported to be associated with global warming.However,confined to the low spatial resolution of energy consumption statistical data,details of AHF was not well descripted.To obtain high spatial resolution data of AHF,Defense Meteorological Satellite Program/Operational Linescan System(DMSP/OLS)nighttime light time-series product and Moderate Resolution Imaging Spectroradiometer(MODIS)satellite monthly normalized difference vegetation index(NDVI)product were applied to construct the human settlement index.Based on the spatial regression relationship between human settlement index and energy consumption data.A 1-km resolution dataset of AHF of 12 selected cities in the eastern China was obtained.Ordinary least-squares(OLS)model was applied to detect the mechanism of spatial patterns of AHF.Results showed that industrial emission in selected cities of the eastern China was accountable for 63%of the total emission.AHF emission in megacities,such as Tianjin,Jinan,Qingdao,and Hangzhou,was most significant.AHF increasing speed in most areas in the chosen cities was quite low.High growth or extremely high growth of AHF were located in central downtown areas.In Beijing,Shanghai,Guangzhou,Jinan,Hangzhou,Changzhou,Zhaoqing,and Jiangmen,a single kernel of AHF was observed.Potential influencing factors showed that precipitation,temperature,elevation,normalized different vegetation index,gross domestic product,and urbanization level were positive with AHF.Overall,this investigation implied that urbanization level and economic development level might dominate the increasing of AHF and the spatial heterogeneousness of AHF.Higher urbanization level or economic development level resulted in high increasing speeds of AHF.These findings provide a novel way to reconstruct of AHF and scientific supports for energy management strategy development.

Estimation of the Distribution of Global Anthropogenic Heat Flux

The radiance lights data in 2006 from the National Oceanic and Atmospheric Administration Air Force Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) and authoritative energy data distributed by the United State Energy Information Administration were applied to estimate the global distribution of anthropogenic heat flux.A strong linear relationship was found to exist between the anthropogenic heat flux and the DMSP/OLS radiance data.On a global scale,the average value of anthropogenic heat flux is approximately 0.03 W m 2 and 0.10 W m 2 for global land area.The results indicate that global anthropogenic heat flux was geographically concentrated and distributed,fundamentally correlating to the economical activities.The anthropogenic heat flux concentrated in the economically developed areas including East Asia,Europe,and eastern North America.The anthropogenic heat flux in the concentrated regions,including the northeastern United States,Central Europe,United Kingdom,Japan,India,and East and South China is much larger than global average level,reaching a large enough value that could affect regional climate.In the center of the concentrated area,the anthropogenic heat flux density may exceed 100 W m 2,according to the results of the model.In developing areas,including South America,Central and North China,India,East Europe,and Middle East,the anthropogenic heat flux can reach a level of more than 10 W m 2 ;however,the anthropogenic heat flux in a vast area,including Africa,Central and North Asia,and South America,is low.With the development of global economy and urban agglomerations,the effect on climate of anthropogenic heat is essential for the research of climate change.

Anthropogenic Heat Flux Will Affect Global Warming

Examination of 420,000 years old ice cores shows a close relation between temperature increase and CO2-concentration increase. During the industrial era a new energy component appears, Anthropogenic Heat Flux, and a part of that energy will accumulate in Earth climate system and become an essential part of global warming.

Simulation and analysis for anthropogenic heat release

Heat balance of urban ecosystem is a key point for the study of urban climate and micro-climate pattern and its change mechanism. Urban heat island effect is becoming increasingly serious,which is mainly caused by the change of the earth's surface cover and the anthropogenic heat release. In this study,the simulation experiment for the anthropogenic heat release was designed according to the heat balance principle. A set of buildings of miniature city were used to constitute the residential area,U grooves were applied to simulate the single building,and the fluorescent lamps in the U groove were regarded as the heat sources of the anthropogenic heat release. The simulation experiment was launched with long-short wave sun photometer,sonic anemothermometer and heat flow gauge in the experiment site. Then the net solar radiation,sensible heat flux and heat flux into the ground were determined. The quantities of the anthropogenic heat release were calculated based on the heat balance principle,and were compared with the theoretical power consumption of the fluorescent lamps. The root mean square error( RMSE) of the simulation for the anthropogenic heat release reaches0. 078 W·m- 2,a comparatively high precision,which showes that the anthropogenic heat release can be accurately determined through the simulation experiments. This study provided a scientific method for the purpose of monitoring the anthropogenic heat release.

Simulation of interaction between high-temperature process and heat emission from electricity system in summer

During the hot summer season,using electricity systems increases the local anthropogenic heat emission,further increasing the temperature.Regarding anthropogenic heat sources,electric energy consumption,heat generation,indoor and outdoor heat transfer,and exchange in buildings play a critical role in the change in the urban thermal environment.Therefore,the Weather Research and Forecasting(WRF)Model was applied in this study to investigate the heat generation from an indoor electricity system and its influence on the outdoor thermal environment.Through the building effect parameterization(BEP)of a multistorey urban canopy scheme,a building energy model(BEM)to increase the influence of indoor air conditioning on the electricity consumption system was proposed.In other words,the BEP+BEM urban canopy parameterization scheme was set.High temperatures and a summer heat wave were simulated as the background weather.The results show that using the BEP+BEM parameterization scheme of indoor and outdoor energy exchange in the WRF model can better simulate the air temperature near the surface layer on a sunny summer.During the day,the turning on the air conditioning and other electrical systems have no obvious effect on the air temperature near the surface layer in the city,whereas at night,the air temperature generally increases by 0.6℃,especially in densely populated areas,with a maximum temperature rise of approximately 1.2℃from 22:00 to 23:00.When the indoor air conditioning target temperature is adjusted to 25-27℃,the total energy release of the air conditioning system is reduced by 12.66%,and the temperature drops the most from 13:00 to 16:00,with an average of approximately 1℃.Further,the denser the building is,the greater the temperature drop.

Exploring diurnal and seasonal variabilities in surface urban heat island intensity in the Guangdong-Hong Kong-Macao Greater Bay Area

The urban heat island(UHI) is an environmental problem of wide concern because it poses a threat to both the human living environment and the sustainable development of cities. Knowledge of the spatiotemporal characteristics and the driving factors of UHI is essential for mitigating their impact. However, current understanding of the UHI in the Guangdong–Hong Kong–Macao Greater Bay Area(GBA) is inadequate. Combined with data(e.g., land surface temperature and land use.) acquired from the Google Earth Engine and other sources for the period 2001–2020, this study examined the diurnal and seasonal variabilities, spatial heterogeneities, temporal trends, and drivers of surface UHI intensity(SUHII) in the GBA. The SUHII was calculated based on the urban–rural dichotomy, which has been proven an effective method. The average SUHII was generally 0–2°C, and the SUHII in daytime was generally greater than that at night. The maximum(minimum) SUHII was found in summer(winter);similarly, the largest(smallest) diurnal difference in SUHII was during summer(winter). Generally, the Mann–Kendall trend test and the Sen's slope estimator revealed a statistically insignificant upward trend in SUHII on all time scales. The influence of driving factors on SUHII was examined using the Geo-Detector model. It was found that the number of continuous impervious pixels had the greatest impact, and that the urban–rural difference in the enhanced vegetation index had the smallest impact, suggesting that anthropogenic heat emissions and urban size are the main influencing factors. Thus, controlling urban expansion and reducing anthropogenic heat generation are effective approaches for alleviating surface UHI.

Estimation of the Anthropogenic Heat Release Distribution in China from 1992 to 2009

Stable light data from Defense Meteorological Satellite Program （DMSP）/Operational Linescan System （OLS） satellites and authoritative energy consumption data distributed by National Bureau of Statistics of China were applied to estimating the distribution of anthropogenic heat release in China from 1992 to 2009. A strong linear relationship was found between DMSP/OLS digital number data and anthropogenic heat flux density （AHFD）. The results indicate that anthropogenic heat release in China was geographically concentrated and was fundamentally correlated with economic activities. The anthropogenic heat release in economically developed areas in northern, eastern, and southern China was much larger than other regions, whereas it was very small in northwestern and southwestern China. The mean AHFD in China increased from 0.07 W m-2 in 1978 to 0.28 W m-2 in 2008. The results indicate that in the anthropogenic heat- concentrated regions of Beijing, the Yangtze River Delta, and the Pearl River Delta, the AHFD levels were much higher than the average. The effect of aggravating anthropogenic heat release on climate change deserves further investigation.

Impact of anthropogenic heat emissions on meteorological parameters and air quality in Beijing using a high-resolution model simulation

Anthropogenic heat emissions(AHE)play an important role in modulating the atmospheric thermodynamic and kinetic properties within the urban planetary boundary layer,particularly in densely populated megacities like Beijing.In this study,we estimate the AHE by using a Large-scale Urban Consumption of energY(LUCY)model and further couple LUCY with a high-resolution regional chemical transport model to evaluate the impact of AHE on atmospheric environment in Beijing.In areas with high AHE,the 2-m temperature(T_(2))increased to varying degrees and showed distinct diurnal and seasonal variations with maxima in night and winter.The increase in 10-m wind speed(WS_(10))and planetary boundary layer height(PBLH)exhibited slight diurnal variations but showed significant seasonal variations.Further,the systematic continuous precipitation increased by 2.1 mm due to the increase in PBLH and water vapor in upper air.In contrast,the precipitation in local thermal convective showers increased little because of the limited water vapor.Meanwhile,the PM_(2.5) reduced in areas with high AHE because of the increase in WS_(10) and PBLH and continued to reduce as the pollution levels increased.In contrast,in areas where prevailing wind direction was opposite to that of thermal circulation caused by AHE,the WS_(10) reduced,leading to increased PM_(2.5).The changes of PM_(2.5) illustrated that a reasonable AHE scheme might be an effective means to improve the performance of PM_(2.5) simulation.Besides,high AHE aggravated the O_(3) pollution in urban areas due to the reduction in NO_(x).

Analysis of observations on the urban surface energy balance in Beijing

The 1-year（2009-2010） measurements are analyzed of the urban surface energy balance（SEB） obtained from the sensors located at three vertical layers of a 325-m tower in downtown Beijing.Results show that：（1） The measurements from the 325-m tower represent the SEB characteristics of the cities located in semi-humid warm-temperate continental monsoon climate zone.In a typical hot and rainy summer,cold and dry winter,the measured Bowen ratio is minimum in summer and maximum in winter.The Bowen ratio measured at 140 m for spring,summer,autumn,and winter are 2.86,0.82,1.17,and 4.16 respectively.（2） At the height of 140-m（in the constant flux layer）,the noontime albedo is ~0.10 for summer,~0.12 for spring and autumn,and ~0.14 for winter.The ratios of daytime sensible heat flux,latent heat flux,and storage heat flux to net radiation are 0.25,0.16,and 0.59 for clear-sky days,and 0.33,0.19,and 0.48 for cloudy days respectively.（3） Under clear-sky days,the nighttime sensible heat flux is almost zero,but the latent heat flux is greater than zero.For cloudy days,the nighttime sensible heat flux is slightly greater than the latent heat flux in winter.The nighttime upward heat flux is presumably due to the anthropogenic release（mainly latent heat for summer,while latent and sensible heat for winter）.

Snowdrift effect on snow deposition：Insights from a comparison of a snow pit profile and meteorological observations in east Antarctica

A high-frequency and precise ultrasonic sounder was used to monitor precipitated/deposited and drift snow events over a 3-year period(17 January 2005 to 4 January 2008) at the Eagle automatic weather station site,inland Antarctica.Ion species and oxygen isotope ratios were also generated from a snow pit below the sensor.These accumulation and snowdrift events were used to examine the synchronism with seasonal variations of δ^(18)O and ion species,providing an opportunity to assess the snowdrift effect in typical Antarctic inland conditions.There were up to 1-year differences for this 3-year-long snow pit between the traditional dating method and ultrasonic records.This difference implies that in areas with low accumulation or high wind,the snowdrift effect can induce abnormal disturbances on snow deposition.The snowdrift effect should be seriously taken into account for high-resolution dating of ice cores and estimation of surface mass balance,especially when the morphology of most Antarctic inland areas is similar to that of the Eagle site.