Kaicun Wang

Peking University | PKU

Digital elevation models (DEMs) have important meteorological, hydrological, and climatological applications. This research studies the uncertainties of six widely accepted global DEM datasets over China and their derivative parameters, including slope and aspect, in calculating the surface-received solar radiation and extracting the river networks...

Global air temperature has become the primary metric for judging global climate change. The variability of global temperature on a decadal timescale is still poorly understood. This paper examines further one suggested hypothesis, that variations in solar radiation reaching the surface (Rs) have caused much of the observed decadal temperature varia...

1] This review surveys the basic theories, observational methods, satellite algorithms, and land surface models for terrestrial evapotranspiration, E (or lE, i.e., latent heat flux), including a long-term variability and trends perspective. The basic theories used to estimate E are the Monin-Obukhov similarity theory (MOST), the Bowen ratio method,...

Visibility in the clear sky is reduced by the presence of aerosols, whose types and concentrations have a large impact on the amount of solar radiation that reaches Earth's surface. Here we establish a global climatology of inverse visibilities over land from 1973 to 2007 and interpret it in terms of changes in aerosol optical depth and the consequ...

Atmospheric downward longwave radiation at the surface (Ld) varies with increasing CO2 and other greenhouse gases. This study quantifies the uncertainties of current estimates of global Ld at monthly to decadal timescales and its global climatology and trends during the past decades by a synthesis of the existing observations, reanalyses, and satel...

Since the 1950s, precipitation has been measured at national weather stations in China using national standard precipitation gauges. Gauges without wind fence can significantly underestimate precipitation amounts, while this undercatch bias is closely related to surface wind speed and precipitation type. The observed surface wind speed across China...

The internal intensity distributions of precipitation systems are closely related to precipitation dynamics. Understanding its climatology and changing characteristics is important for comprehending climate change, enhancing atmospheric model, and obtaining accurate hydrologic responses. However, due to the various limitations of precipitation obse...

The observed surface wind speed (SWS) over China has declined in the past four decades, and recently, the trend has reversed, which is known as SWS stilling and recovery. The observed SWS is vulnerable to changes in nonclimatic factors, i.e., inhomogeneity. Unfortunately, most of the existing studies on the long-term trend of SWS were based on raw...

Meteorological observations provide essential data for weather forecasting and climate change studies. Whether the measured data can accurately support such applications closely relates to the representativeness of the data collected, which depends on both the scale of observation and the density of the measurement network. Precipitation presents i...

2019 年以来国家自然科学基金委员会（简称“自然科学基金委”）深入推进新时代科学基金改革，在 此背景下地球科学部大气学科率先开展了申请代码调整，助力优化学科资助布局，确定了以“分支学科、支撑技 术和发展领域”三大类，共 15 个二级申请代码为主要架构的学科资助体系，并组织专家对各二级申请代码的下 设研究方向和关键词进行系统梳理和调整。应用气象学作为学科二级申请代码之一（D0515），主要研究方向包 括：（1）人工影响天气；（2）农林气象；（3）水文气象；（4）资源气象；（5）交通气象；（6）其他应用气 象方向。本文从服务申请人的角度出发，梳理了应用气象学二级申请代码内涵和外延的演变，介绍了应用气象学 二级申请代码下的关键词，结合文献检索，分析了这些关键词在国内外科研前沿和基金项目申请书中的...

As the Earth's primary energy source, surface downward solar radiation (R s) determines the solar power potential and usage for climate change mitigation. Future projections of R s based on climate models have large uncertainties that interfere with the efficient deployment of solar energy to achieve China's carbon neutrality goal. Here we assess 2...

The energy balance at the top of the atmosphere (TOA) and at the surface of the earth plays an essential role in the earth's climate change. The Clouds and Earth Radiant Energy System (CERES) can directly measure the energy radiation at the TOA, while the surface energy balance needs to be estimated by satellite retrievals and atmospheric reanalysi...

Drought can develop rapidly over a short period, the so-called “flash drought”. The widely used standardized precipitation evapotranspiration index (SPEI), with traditional time scales longer than one month, cannot easily capture flash drought signals. Here, the SPEI with a five-day (pentad) time scale was proposed to investigate flash droughts in...

How precipitation responds to global warming has drawn much interest from the scientific community. However, as one of the important properties of precipitation, changes in the precipitation system scale have rarely been studied. The latest retrospective merged satellite precipitation product has provided a great opportunity to investigate quasi-gl...

One of the major advantages of satellite precipitation estimates is that they can provide a complete picture of precipitation systems; a difficult task to achieve using sparsely distributed rain gauges. This advantage greatly enhances our understanding of natural precipitation. Also, for this reason, it is difficult to know satellite-derived precip...

Projecting mitigations of carbon neutrality from individual countries in relation to future global warming is of great importance for depicting national climate responsibility but is poorly quantified. Here, we show that China’s carbon neutrality (CNCN) can individually mitigate global warming by 0.48 °C and 0.40 °C, which account for 14% and 9% of...

The frequency of extreme climate events has escalated since 1980. In February 2021, an unprecedented winter storm dumped the snow record in Texas. It claimed hundreds of lives and evolved into a national major disaster. However, we still lack a systematic approach to quantify large-scale snow depth. Here, we use the differential coherence from Sent...

Rainfall and snowfall have different effects on energy balance calculations and land–air interactions in terrestrial models. The identification of precipitation types is crucial to understand climate change dynamics and the utilization of water resources. However, information regarding precipitation types is not generally available. The precipitati...

Surface incident solar radiation (Rs) plays a key role in climate change on Earth. Rs can be directly measured, and it shows substantial variability on decadal scales, i.e. global dimming and brightening. Rs can also be derived from the observed sunshine duration (SunDu) with reliable accuracy. The SunDu-derived Rs has been used as a reference to d...

The observed surface wind speed (SWS) has declined across China over the last four decades, but the mechanisms responsible for this decline have been explored without reaching a consensus. In this study, we develop a physical method to quantify and adjust for the impact of urbanization around weather stations on the observed SWS over China from 198...

Changes in precipitation seasonality or the distribution of precipitation have important impacts on hydrological extremes (e.g., floods or droughts). Precipitation extremes have been widely reported to increase with global warming; however, the variability and mechanism of precipitation seasonality have not been well quantified in China. Here, we e...

Precipitation is spatially and temporally unevenly distributed. The unevenness of precipitation is crucial for climate change, as well as for water resource management, environmental risk reduction, and industrial/agricultural production. In this study, gauge observations and eight reanalysis products are used to examine the unevenness of precipita...

Hourly precipitation is important in climate research because it is closely related to convective synoptic systems and short-term weather forecasts. In this study, characteristics like climatology, inter-annual variability and diurnal cycle are quantified from 1979 to 2015 over eastern China using hourly gauge observations and ERA5 precipitation da...

Surface incident solar radiation (Rs) plays an essential role in climate change on Earth. Rs can be directly measured, and it shows substantial variability, i.e., global dimming and brightening, on decadal scales. Rs can also be derived from the observed sunshine duration (SunDu) with reliable accuracy. The SunDu-derived Rs was used as a reference...

A variety of drought indices have been constructed to monitor agricultural drought using ground-based observations and satellite data. The drought indices focus on diverse aspects of agricultural drought and may have diverse applicability in different regions. We calculated seven popular drought indices and evaluated their performances on monitorin...

Lake ice phenology is a climate-sensitive indicator. However, ground-based monitoring suffers from the limitations of human vision and the difficulty of its implementation in harsh environments. Remote sensing provides great potential to detect lake ice phenology. In this study, a new automated method was developed to extract lake ice phenology par...

Estimating future temporal patterns of Surface Urban Heat Islands (SUHIs) on multiple time scales is an ongoing research endeavor. Among these time scales, estimation of next-day SUHIs is of special significance to urban residents, yet we currently lack a simple but efficient approach for making such estimations. In the present study, we propose a...

The size of precipitation systems is an important parameter of precipitation process and dynamics. This study uses the latest Integrated Multi-satellitE Retrievals for Global Precipitation Measurement data during 2015–2019 to investigate the global distribution of precipitation system size, its spatial and temporal pattern, as well as its relations...

Surface incident solar radiation (Rs) is important for providing essential information on climate change. Existing studies have shown that the Rs values from current reanalyses are significantly overestimated throughout China. The European Centre for Medium-Range Weather Forecasts (ECMWF) recently released the fifth generation of atmospheric reanal...

Precipitation has an important impact on crop growth, water resources, industrial/agricultural production, and ecological services. Compared to widely used precipitation amount, intensity of precipitation is more important because it determines the partition of precipitation into soil moisture and surface runoff. With hourly precipitation observati...

The observed surface wind speed (SWS) has declined over the past four decades over China, which have has been examined from a climatological perspective. However, the SWS is highly variable and is dependent on the weather regime (WR). This study investigates the variability of winter SWS under six typical WRs and assesses the variability at the syn...

Although great progress has been made in estimating surface solar radiation (Rs) from meteorological observations, satellite retrieval, and reanalysis, getting best-estimated long-term variations in Rs are sorely needed for climate studies. It has been shown that Rs data derived from sunshine duration (SunDu) can provide reliable long-term variabil...

Surface solar radiation (Rs) is essential to climate studies. Thanks to long-term records from the Advanced Very High-Resolution Radiometers (AVHRR), the recent release of International Satellite Cloud Climatology Project (ISCCP) HXG cloud products provide a promising opportunity for building long-term Rs data with high resolutions (3 h and 10 km)....

The 2019 extreme wildfire in South China was largely related to both anthropogenic warming and El Nino event. They increased the weather-related risk of extreme wildfire by 7.2 times and 3.6 times, respectively

The record-low January–February 2019 sunshine in the Middle-Lower Yangtze Plain was favored by a circulation pattern, while anthropogenic aerosols and greenhouse gases increased their probability in recent decades by 3.1 and 1.3 times, respectively.

Evaluations of satellite precipitation products have been routinely conducted, often by calculating statistical indicators on fixed time intervals (e.g., hourly and daily). However, precipitation is actually a discontinuous variable in the form of events. Event‐based evaluations could provide additional information to those based on fixed‐interval...

Snow depth is a critical variable that reflects snow variability and has an important impact on the energy and hydrological cycles. However, snow depth changes in response to regional climate warming have not been quantified in detail across China. Here, we investigated the variability in observed snow depth based on a recently released dataset col...

The annual temperature cycle affects atmospheric circulation, biomass cycling, and human life. Its variation is influenced by surface solar radiation, which plays a key role in surface energy budgets. In this study, the Fourier transform method is used to analyse the spatial distribution and long‐term variations in temperature phase, amplitude, and...

Although great progress has been made in estimating surface solar radiation (Rs) from meteorological observations, satellite retrieval and reanalysis, getting best estimated of long-term variations in Rs are sorely needed for climate studies. It has been shown that sunshine duration (SunDu)-derived Rs data can provide reliable long-term Rs variatio...

Most previous studies of surface urban heat islands (SUHIs) have focused solely on their controlling factors on a seasonal/annual timescale, while the controls on daily variations are largely unknown. By extracting the daily variations of nighttime SUHI features using the Gaussian model and investigating their correlations with various explanatory...

The increasing rate of the observed daily minimum temperature (Tmin) has been much higher than that of the observed daily maximum temperature (Tmax) during the past six decades across China. In this study, the local urbanization impact on this observed asymmetric warming rates was investigated. The latest released land cover data with a 30-meter sp...

Land surface temperature (Ts) and near surface air temperature (Ta) are two main metrics that reflect climate change. Recently, based on in situ observations, several studies found that Ts warmed much faster than Ta in China, especially after 2000. However, we found abnormal jumps in the Ts time series during 2003-2005, were mainly caused by the tr...

On behalf of the journal, AGU, and the scientific community, the editors would like to sincerely thank those who reviewed the manuscripts for Geophysical Research Letters in 2019. The hours reading and commenting on manuscripts not only improve the manuscripts but also increase the scientific rigor of future research in the field. We particularly a...

Dust aerosols are a major type of aerosol over the Tibetan Plateau (TP) and influence climate at local to regional scales through their effects on thermal radiation and snow‐albedo feedback. Based on the Modern‐Era Retrospective Analysis for Research and Applications, Version 2 (MERRA‐2) aerosol data set, we report an increase of 34% in the atmosph...

The near-surface lapse rate reflects the atmospheric stability above the surface. Lapse rates calculated from land surface temperature () and near-surface air temperature () have been widely used. However, and have different sensitivity to local surface energy balance and large-scale energy transport and therefore they may have diverse spatial and...

Air pollution over China has attracted wide interest from public and academic community. PM2.5 is the primary air pollutant across China. Quantifying interactions between meteorological conditions and PM2.5 concentrations are essential to understand the variability of PM2.5 and seek methods to control PM2.5. Since 2013, the measurement of PM2.5 has...

Future climate change predictions by global climate models or earth system models diverge significantly, most likely due to their different cloud responses to global warming. There is an uncertainty as to how the cloud frequency (or cloud fraction) and height will change, in turn, affecting the sign and amount of cloud feedbacks. While satellite ob...

Surface wind speed (SWS) from meteorological observation, global atmospheric reanalysis, and geostrophic wind speed (GWS) calculated from surface pressure were used to study the stilling and recovery of SWS over China from 1960 to 2017. China experienced anemometer changes and automatic observation transitions in approximately 1969 and 2004, result...

In response to a growing demand for subnational and spatially explicit data on China’s future population, this study estimates China’s provincial population from 2010 to 2100 by age (0–100+), sex (male and female) and educational levels (illiterate, primary school, junior-high school, senior-high school, college, bachelor’s, and master’s and above)...

The Tropical Rainfall Measurement Mission (TRMM) satellite is the first to be designed to measure precipitation, and its precipitation products have been assessed in a variety of ways. Data for its post-real-time level 2 product (3B42) performed well in terms of the precipitation amount at the monthly scale because they were corrected by a precipit...

The averaged near-surface air temperature (Ta) of July–August 2018 over Northeast China is ~1.73°C above the 1971–2000 mean, the highest since 1961. One-third of the stations in the region broke the historical record (Figs. 1a,b), which posed a great threat to local ecosystems and human health because this region has seldom experienced such extreme...

During the winter of 2017/18, Beijing endured the longest consecutive dry day spell (CDD) (145 days; 23 October 2017–16 March 2018) since recordings began in 1951. There was no effective precipitation during this period, and there was no snow in the winter (November–February) for Beijing for the first time. As a result, the total precipitation was...

Lake surface water temperature (LSWT) plays a fundamental role in the lake energy budget. However, direct observations of LSWT require considerable effort for acquisition and hence are rare relative to a large number of lakes. In lakes where LSWT has not been covered sufficiently by in situ measurements, remote sensing and lake modeling can be used...

https://authors.elsevier.com/c/1acKM9pi-Pu4Z Modeling studies have focused on N2O emissions in temperate rivers under static atmospheric N2O (N2Oairc), with cold temperate river networks under dynamic N2Oairc receiving less attention. To address this knowledge and methodological gap, the dissolved N2O concentration (N2Odisc) and N2Oairc algorithms...

Plain Language Summary The direct solar radiation (Rdir) and diffuse solar radiation (Rdif) dominate plant photosynthesis. In particular, due to higher light‐use efficiency for canopy photosynthesis under Rdif than Rdir, changes of fraction of Rdif to Rdir could substantially alter plant productivity and the efficiency of canopy gas exchange. Howev...

Summer temperature dominates environmental degradation and water resource availability on the Tibetan Plateau (TP), such as glacier melting, permafrost degradation, desertification and streamflow, etc. Extending summer temperature records back before the instrumental period is fundamentally important for climatic and environmental studies over long...