Most Parts Of China Research Articles

Stilling and its aerodynamic effects on pan evaporation

Declines in wind speed (u) (termed as “stilling”) has been reported in many regions of the world. To explore the temporal trends of u and its aerodynamics effects is vital to understand the changes in water resources. This study analyzed the changes of temporal trends for u and its aerodynamic effects using the data during 1959-2000 at 266 stations across China. The improved PanPen model was used to estimate Epan and quantify the contribution of radiative and aerodynamic components (aerodynamic component separated into wind speed u, vapour pressure deficit D, and air temperature Ta). Climate factors include Epan measured with the standard Chinese 20 cm diameter pan, u, Ta, relative humidity (rh) and sunshine hours (sh). The results showed: stilling occurred in most of stations (206 among 266) and 105 stations presented significant decreasing trends at 99% confidence level; stilling was the main cause for controlling the trends in Epan in most part of China, especially in the west and north of China. The results indicated that decreasing trends in Epan due to stilling would inevitably alter water resources, and should be put further investigation incorporation other factors.

The two leading modes of winter clear-sky days over China and their formation mechanisms

Using gauge data during 1979–2013, the spatial and temporal characteristics of winter clear-sky days (CSDs) in China are investigated. The frequency of winter CSDs in China has two independent and significant modes, which account for 41% and 10% of the total variance, respectively. Based on evidence from observational analysis and numerical experiments, the formation mechanisms of these two leading modes are unraveled. The first mode is a homogenous mode with coherent year-to-year variation of CSDs over most parts of China, and is closely related to a large-scale cyclonic/anticyclonic anomaly over the Asian continent. Anomalous Indian Ocean SST and Arctic sea ice are responsible for the associated large-scale circulation anomalies via inducing a mid-to-high latitude Rossby wave train. The Indian Ocean SST warming can induce wave energy propagation upwards to the stratosphere and then northwards to the polar region, where it moves down to the troposphere and then travels southeastwards from the polar region to East Asia. Meanwhile, the decreased Arctic sea ice can directly induce a Rossby wave train emanating from the polar region that travels southeastwards into East Asia. These two factors jointly lead to a dominant equivalent barotropic cyclonic/anticyclonic anomaly over China, and in turn the homogenous pattern of winter CSDs in the region. The second mode is a seesaw mode with out-of-phase variations of CSDs between northern and southern China. This mode is closely related to a meridional dipole circulation anomaly pattern over the East Asian sector, which is generated by the so-called ‘Mega-ENSO’ SST anomaly over the Pacific Ocean. This Mega-ENSO SSTA pattern can induce convective heating/cooling over the tropical western Pacific, which further leads to the meridional dipole circulation anomaly pattern over the East Asian sector, resulting in the south-to-north seesaw mode of winter CSDs in China.

An operational statistical downscaling prediction model of the winter monthly temperature over China based on a multi-model ensemble

The interannual variation of East Asian winter surface air temperature (SAT) exhibits considerable differences between individual months. However, the prediction skill of dynamical models is rather low; therefore, a statistical downscaling (SD) model was employed to improve the skill for 36 winters during 1983/84–2018/19 in a cross-validated method and for 6 winters during 2013/14–2018/19 in an independent verification. The first two observed empirical orthogonal function (EOF) modes of monthly mean SAT variability explain about 60%–70% of the total variance. Correlation analysis of EOF principal components (PCs) is applied to explore the predictability from key lower boundary anomalies, i.e., Arctic sea ice and sea surface temperature (SST), for SD models. Two previous or simultaneous predictors over distinct areas are identified by the PC correlation analysis for individual monthly China SAT. It is assumed that the simultaneous SST predictors from the multi-model ensemble (MME) of Climate Forecast System version 2 (CFSv2) and BCC_CSM1.1 m involved in the SD model are perfectly predicted, and the potential attainable predictability can be obtained to qualify the highest prediction skills of the SD model. During 1983/84–2018/19, the area-averaged temporal correlation coefficient (TCC) skill of the MME model is 0.10, 0.26 and 0.30 (0.27 at the 90% confidence level) for December, January and February, respectively. The significantly high skill of the cross-validated SD forecast mainly covers extensive domains in central China, and the area-averaged TCC skill is improved compared with the original MME prediction. The corresponding area-averaged attainable TCC skills are 0.26, 0.46 and 0.50 in the SD model, with reference to significant TCC regions in most parts of China. The pattern correlation coefficient skill of the original MME model is much lower than that of the SD model prediction. Independent SD forecasting for a recent 6-year period further reveals that the winter monthly China SAT is highly predictable by the SD model. It should be noted that the China SAT in December is less predictable than that in January and February by the dynamical and SD models, which may be due to the complex predictability source of December SAT. During January and February, the El Niño–Southern Oscillation signal and Indian Ocean dipole mode can be considered as one of the prominent sources of predictability leading to a better prediction skill.

The use of combined soil moisture data to characterize agricultural drought conditions and the relationship among different drought types in China

Drought monitoring and assessment are of great importance due to the costly damage caused by drought. Datasets, drought indexes and drought relationships are three critical areas of drought research. Satellite-retrieved soil moisture (SM) products derived from the European Space Agency Climate Change Initiative (ESA CCI) show application potential in drought monitoring. However, the products are missing certain data in some areas. The model-assimilated SM product derived from the Global Land Data Assimilation System (GLDAS) was used to supplement these missing data. The main goals of this paper are to characterize agricultural drought after the utility and applicability of the combined SM product and the monthly scaled soil water deficit index (SWDI) have been evaluated and to investigate the relationships among meteorological, agricultural and vegetation droughts. First, we provided a long series of highly accurate SM products through simple calculations. The drought index, SWDI, was extended to a monthly scale for long-term drought analysis by using the combined SM product. The probability of detection (POD) between the SWDI and in situ drought records performed fairly well. Half of the 566 stations had PODs higher than 0.9, and one-third of these stations had POD values equal to 1. Through correlation analysis and grey incidence analysis (GIA) between the standardized precipitation index (SPI) and SWDI, we found that the propagation time from meteorological drought to agricultural drought was shorter under drier conditions than wetter conditions, and at the regional scale, the response time ranged from 1 month to 2.5 months. Correlation analysis between the SWDI and vegetation condition index (VCI) indicated that there was no delay effect from agricultural to vegetation drought on a monthly scale in most parts of China except in several provinces distributed in the South; additionally, there was a significant time lag in forests, while grassland and agriculture were more inclined to have no time lag or the response time was less than 1 month.

A survey about the contents and features of oncology clinical pharmacy services and self-evaluations of the oncology pharmacists in China.

In China, with the increased number of oncology patients and use of novel antitumour drugs, the demand of oncology clinical pharmacy services is also growing. However, the current status of oncology clinical pharmacy services in China was seldom reported. The purpose of the study was to investigate the contents and features of oncology clinical pharmacy services and self-evaluations of the oncology pharmacists in China, and to identify related problems for further development. A 55-item online questionnaire was distributed to oncology-related clinical pharmacists in Chinese hospitals in January 2019. Pharmacists answered the questions on the WeChat platform. Data were analysed using descriptive statistics. The respondents of the 166 valid questionnaires were from 29 provinces (or autonomous regions or municipalities). Their average working experience for clinical pharmacy was 4.86years. The average duration of their clinical services was 3.27h/d. The clinical pharmacy services consist of 15 types, and their workload on each service type was summarized. Pharmacists are not frequently participating in establishing pharmacotherapy protocols, therapeutic drug monitoring and pharmacogenetic/pharmacogenomic services. About 80% (81.33%) of the pharmacists thought that other healthcare professionals knew the nature of their work. The biggest barrier for career development of the pharmacists was insufficiency of professional skills. In most cases, the clinical service accounted for <30% of the overall performance evaluation of the pharmacists. Most of the participating pharmacists were not satisfied with their current salary. The overall evaluation score for their career happiness was 6.27 out of 10. The value of oncology clinical pharmacists is being increasingly recognized, but advanced services need further expansion. Increasing the time serving in patient care, optimizing performance evaluation mechanisms and strengthening their skills are possible ways for pharmacists to provide superior services. This study showed the current service of oncology clinical pharmacists in most parts of China, which may provide reference for policymakers, promote international communications and shed light on future development of oncology clinical pharmacy.

Child psychiatry in China: Present situation and future prospects.

Child psychiatry in China: Present situation and future prospects.

The impact of synoptic patterns on summertime ozone pollution in the North China Plain

Surface ozone pollution is a challenging environmental issue in most parts of China. In particular, the North China Plain (NCP) region suffers from the severest ozone pollution throughout the country. In addition to the emission of precursors, ozone concentration is closely related to meteorological conditions resulting from regional atmospheric circulation. In this study, we investigate the relationship between synoptic patterns and summertime ozone pollution in the NCP using the objective principal component analysis in T-mode (T-PCA) classification method. Four dominant synoptic patterns are identified during the summers of 2014–2018. The heaviest ozone pollution is found to be associated with a high pressure anomaly over the Northwest Pacific and a distinct low pressure center in Northeast China. The southwesterly wind surrounding the low pressure center brings dry, warm air from inland South China, resulting in a high temperature, low humidity environment in the NCP, which favors the chemical formation of surface ozone. Locally, this type is associated with a moderate planetary boundary layer height (PBLH) of ~860 m and a stronger warm anomaly within the boundary layer than the upper level. We also notice a non-linear relationship between surface ozone concentration and the PBLH, i.e., ozone concentration first increases with PBLH till ~0.9 km, and then remains stable. This initial increase may relate to enhanced mixing with upper levels where ozone concentration is typically higher than that near the surface. However, when PBLH further increases, this downward mixing effect is balanced with the stronger upward turbulent mixing so that surface ozone shows little change. The synoptic patterns identified here, however, is unlikely responsible for the observed increasing trend in ozone concentration over the NCP region. Our study sheds light on the meteorological contribution to surface ozone pollution in North China and provides a reference for the pollution control and prediction.

Evaluation of nine sub-daily soil moisture model products over China using high-resolution in situ observations

Reliable soil moisture (SM) estimates are not only crucial for the climate variability but are also significant for agricultural, ecological, climatic, and hydrometeorological predictions. With the development of land surface models (LSMs) and multi-source data merging techniques, various SM model products can serve as alternatives to obtain spatially continuous and temporally complete SM estimates. The nine SM model products (0–10 cm), including one analysis, three reanalyses, and five Land Data Assimilation System (LDAS) products, are evaluated using the dense (2437 stations after quality control) in situ observations at different timescales (annual to sub-daily) in eight climate regions over mainland China during 2010–2017. The Kling-Gupta efficiency (KGE), a performance metric combining correlation, bias, and variability, is used to quantify the strengths and weaknesses of these products. CLDAS (China Meteorological Administration’s LDAS) performs the best with the optimal median values of KGE and correlation in most subregions from sub-daily to annual timescales, followed by Global LDAS (GLDAS) CLM product. The SM products show large variability for different subregions, timescales, and spatial resolutions. The SM products have better performance in summer than winter. In addition, high-resolution products and LDAS products have the potential to improve the performance. For example, ERA5 outperforms ERA Interim in most parts of China. The markedly better performance of regional product CLDAS than other global products highlights the importance of incorporating hourly rain gauge and surface temperature observations at a finer model resolution. This intercomparison study sheds some light on the capability of the SM products for climate monitoring, weather prediction and model validation.

Characteristics of Household Transmission of COVID-19.

BackgroundSince December 2019, SARS-CoV-2 virus has extended to most parts of China with more than 80 thousand cases and to at least 100 countries with more than 60 thousand international cases by March 15, 2020. Here we applied household cohort study to determine the features of household transmission of COVID-19.MethodsTotal 105 index patients and 392 household contacts were enrolled. Both index patients and household members were inspected by SARS-CoV-2 RT-PCR. The information of all recruited people was extracted from medical records and confirmed or supplemented by telephone interviews. The baseline characteristics of index cases and contact patients were described. Secondary attack rates of SARS-CoV-2 to the contact members were computed and the risk factors for transmission within household were estimated.ResultsSecondary transmission of SARS-CoV-2 developed in 64 of 392 household contacts (16.3%). The secondary attack rate to children was 4% comparing with 17.1% to adults. The secondary attack rate to the contacts within the households with index patients quarantined by themselves since onset of symptoms was 0% comparing with 16.9% to the contacts without index patients quarantined. The secondary attack rate to contacts who were spouses of index cases was 27.8% comparing with 17.3% to other adult members in the households.ConclusionThe secondary attack rate of SARS-CoV-2 in household is 16.3%. Ages of household contacts and spouse relationship with index case are risk factors for transmission of SARS-CoV-2 within household. Quarantine of index patients at home since onset of symptom is useful to prevent the transmission of SARS-Co-2 within household.

A predictive model for COVID-19 spreading

<p indent="0mm">As the novel coronavirus disease 2019 (COVID-19) has become a Public Health Emergency of International Concern, it is greatly significant to accurately predict the disease’s incoming trend. Herein, we performed a stage-rolling Susceptible-Exposed-Infectious-Recovered (SEIR) model to measure the evolution of the basic reproduction number of COVID-19, based on the number of confirmed infections announced by the National Health Commission of the People’s Republic of China. We assumed that the infected number under the spreading of infectious diseases will generally experience two different stages. In the first stage, due to the public’s ignorance of the severity and harmfulness of the disease, the infected population grows exponentially and the process of disease transmission can be considered as the classic SEIR model with a constant basic reproduction number. Consequently, with limited awareness of the epidemic situation, there is a lack of effective preventive measures to control disease transmission. In the second stage, various control measures and medical resources are introduced in succession by the government, as well as the public gradually takes effective preventions (e.g. keep social distance and wear masks) based on the knowledge of the disease transmission. Collectively, the infected population grows much slower than the first stage. We performed a stage-rolling SEIR model, in which the basic reproduction number changes every day. Based on this model, the number of daily basic reproduction is estimated from the daily new infection number. We found that the daily basic reproduction number is expected to decline continually until it is less than 1, which means the eradication of the disease. Leveraging the evolution of the basic reproduction number, we extrapolate the incoming daily basic reproduction number, based on which we further predict the incoming trend of COVID-19 spreading in terms of the daily infection number. Our predictive model estimates that at the end of the epidemic, the total number of infections in China is nearly 14000 except for Hubei Province, and 32000 except for Wuhan city. We also found that in most parts of China, the number of newly confirmed infections increases linearly rather than exponentially before the day of “Wuhan travel restrictions”, implying that the prevention and containing the infected people from Wuhan at the eve of the Spring Festival has been effective from the beginning.

Evaluation of severity changes of compound dry and hot events in China based on a multivariate multi-index approach

Compound dry and hot events have received increasing attention due to their serious impacts on different sectors of the society. Understanding their variability is of critical importance for developing adaptation measures to reduce their adverse impacts. Previous studies have shown increased frequency of these compound events in past decades at regional and global scales; however, the investigation of changes in their severity has been rather rare. The objective of this study is to evaluate severity changes of compound dry and hot events for the warm season during the period 1961–2012 in China using two indices, namely, Standardized Compound Event Indicator (SCEI) and Standardized Dry Hot Index (SDHI), based on monthly precipitation and temperature. Results show a significant increase in the severity of compound dry and hot events in most parts of China, which is mainly dominated by temperature compared to precipitation. In addition, significant increase of the spatial extent of compound dry and hot events at different severity levels in China is observed, with more areas affected by these compound events after the 1990s. For large regions from northeast to southwest China, severe conditions of compound dry and hot events are shown to be associated with high risk of agricultural droughts. Both the two indices show similar trends in the severity of compound dry and hot events, which indicates the robustness of increased spatial and temporal patterns, highlighting the pressing need for improved understanding to reduce their adverse impacts.

林业技术推广在生态林业建设中的问题及其对策

Promoting the continuous and smooth development of ecological environment and forestry projects can effectively adjust the forest area climate, constantly purify the air in the forest area, and effectively avoid the serious desertification within the forest area land, so as to effectively improve the local ecological environment. At the present stage, due to the low promotion and application of technologies related to ecological forestry project construction in most parts of China and the lack of comprehensive and in-depth understanding, a lot of technical problems have emerged in the process of promoting the construction and development of ecological and environmental forestry projects. Based on this, this paper analyzes and explores the problems existing in the forestry technology promotion in the ecological forestry construction.

East Asian Study of Tropospheric Aerosols and their Impact on Regional Clouds, Precipitation, and Climate (EAST‐AIRCPC)

AbstractAerosols have significant and complex impacts on regional climate in East Asia. Cloud‐aerosol‐precipitation interactions (CAPI) remain most challenging in climate studies. The quantitative understanding of CAPI requires good knowledge of aerosols, ranging from their formation, composition, transport, and their radiative, hygroscopic, and microphysical properties. A comprehensive review is presented here centered on the CAPI based chiefly, but not limited to, publications in the special section named EAST‐AIRcpc concerning (1) observations of aerosol loading and properties, (2) relationships between aerosols and meteorological variables affecting CAPI, (3) mechanisms behind CAPI, and (4) quantification of CAPI and their impact on climate. Heavy aerosol loading in East Asia has significant radiative effects by reducing surface radiation, increasing the air temperature, and lowering the boundary layer height. A key factor is aerosol absorption, which is particularly strong in central China. This absorption can have a wide range of impacts such as creating an imbalance of aerosol radiative forcing at the top and bottom of the atmosphere, leading to inconsistent retrievals of cloud variables from space‐borne and ground‐based instruments. Aerosol radiative forcing can delay or suppress the initiation and development of convective clouds whose microphysics can be further altered by the microphysical effect of aerosols. For the same cloud thickness, the likelihood of precipitation is influenced by aerosols: suppressing light rain and enhancing heavy rain, delaying but intensifying thunderstorms, and reducing the onset of isolated showers in most parts of China. Rainfall has become more inhomogeneous and more extreme in the heavily polluted urban regions.

Recent changes in the drought of China from 1960 to 2014

AbstractIn recent years, extreme droughts have been frequent and widespread, and understanding the spatiotemporal variations in drought events in China plays an important role in drought risk management. In this study, using monthly meteorological data at 618 stations, we computed the Standardized Precipitation Evapotranspiration Index with potential evapotranspiration based on the Penman–Monteith equation (SPEI_PM) for drought assessment. Furthermore, we analysed the trend, affected area, frequency and duration of drought in China over the period of 1960–2014 by the piecewise linear regression method (LRM) and Mann–Kendall (MK) method. The results showed that (a) the slight wetting trend reflected during 1960–2014 by the SPEI_PM (0.03/10a (p &gt; .05). This trend was allocated to most parts of northern and southeastern China and was prone to arrive in winter. In contrast, the most significant drying trend was in the Loess Plateau and Yunnan–Kweichow Plateau. (b) The turning point (TP) year of drought trend was 1993. The SPEI_PM was increased in most parts of northern China before 1993 according to the LRM and MK method. However, it decreased after 1993, especially in the south and northwest of China; (c) Over the past 55 years, the areas affected by drought decreased at a rate of −1.23%/10a (p &lt; .05). In detail, these areas decreased at a rate of −3.41%/10a before 1993 (p &lt; .05) and increased at a rate of 2.71%/10a after 1993 (p &gt; .05). (d) The drought frequency in most parts of China was between 15 and 20 during 1960–2014. Furthermore, compared with that in 1960–1977, the drought frequency was decreased in 1978–1995 and then increased in 1996–2014. These findings suggested that the long‐term trend in drought events during 1960–2014 was not significant in China. However, the severity, affected area and frequency of droughts increase after 1993. These results allowed us to understand the changes in the drought across China over the last 55 years, which is important for guiding relevant agricultural activities.

Risk factors and predicted distribution of visceral leishmaniasis in the Xinjiang Uygur Autonomous Region, China, 2005\u20132015

BackgroundVisceral leishmaniasis (VL) is a neglected disease that is spread to humans by the bites of infected female phlebotomine sand flies. Although this vector-borne disease has been eliminated in most parts of China, it still poses a significant public health burden in the Xinjiang Uygur Autonomous Region. Understanding of the spatial epidemiology of the disease remains vague in the local community. In the present study, we investigated the spatiotemporal distribution of VL in the region in order to assess the potential threat of the disease.MethodsBased on comprehensive infection records, the spatiotemporal patterns of new cases of VL in the region between 2005 and 2015 were analysed. By combining maps of environmental and socioeconomic correlates, the boosted regression tree (BRT) model was adopted to identify the environmental niche of VL.ResultsThe fitted BRT models were used to map potential infection risk zones of VL in the Xinjiang Uygur Autonomous Region, revealing that the predicted high infection risk zones were mainly concentrated in central and northern Kashgar Prefecture, south of Atushi City bordering Kashgar Prefecture and regions of the northern Bayingolin Mongol Autonomous Prefecture. The final result revealed that approximately 16.64 million people inhabited the predicted potential infection risk areas in the region.ConclusionsOur results provide a better understanding of the potential endemic foci of VL in the Xinjiang Uygur Autonomous Region with a 1 km spatial resolution, thereby enhancing our capacity to target the potential risk areas, to develop disease control strategies and to allocate medical supplies.

Application of Improved Non-local Mean Filtering Algorithm in Detection of Oil and Gas Wells

As the oil and gas exploration in most parts of China has entered into the middle and late stages, the aging and wear problems of mining equipment have become increasingly prominent. In the process of visual image acquisition of oil and gas well casing damage, due to the influence of the complex environment of light and dust, the image data source noise is serious, and the image recognition model has low accuracy. This paper improves the neighbourhood filtering algorithm block search process with the ant colony pheromone correlation theory, optimizes the block matching process with the Pearson algorithm, and eventually applies the optimized non-local mean filtering algorithm to the oil and gas well casing damage visual detection process. The experimental results show that the improved non-local mean filtering algorithm has a significant impact on the adaptability and effectiveness of the noise reduction effect.

The Spatial–Temporal Variation of Tropospheric NO2 over China during 2005 to 2018

In recent years, new and strict air quality regulations have been implemented in China. Therefore, it is of great significance to evaluate the current air pollution situation and effectiveness of actions. In this study, Ozone Monitoring Instrument (OMI) satellite data were used to detect the spatiotemporal characteristics of tropospheric NO2 columns over China from 2005 to 2018, including spatial distribution, seasonal cycles and long-term trends. The averaged NO2 pollution is higher in southeastern China and lower in the northwest, which are well delineated by the Heihe–Tengchong line. Furthermore, the NO2 loadings are highest in the North China Plain, with vertical column density (VCD) exceeding 13 × 1015 molec cm−2. Regarding the seasonal cycle, the NO2 loadings in eastern China is highest in winter and lowest in summer, while the western region shows the opposite feature. The amplitude of annual range increase gradually from the south to the north. If the entire period of 2005–2018 is taken into account, China has experienced little change in NO2. In fact, however, there appears to be significant trends of an increase followed by a downward tendency, with the turning point in the year 2012. In the former episode of 2005–2012, increasing trends overwhelm nearly the whole nation, especially in the Jing–Jin–Tang region, Shandong Province, and Northern Henan and Southern Hebei combined regions, where the rising rates were as high as 1.0–1.8 × 1015 molec cm−2 year−1. In contrast, the latter episode of 2013–2018 features remarkable declines in NO2 columns over China. Particularly, the regions where the decreased degree was remarkable in 2013–2018 were consistent with the regions where the upward trend was obvious in 2005–2012. Overall, this upward–downward pattern is true for most parts of China. However, some of the largest metropolises, such as Beijing, Shanghai and Guangzhou, witnessed a continuous decrease in the NO2 amounts, indicating earlier and more stringent measures adopted in these areas. Finally, it can be concluded that China’s recent efforts to cut NO2 pollution are successful, especially in mega cities.

Which form of Chinese Characters is More Beneficial to Education: Research of the Influencing Factors Based on Aliquot Linear Regression

There are two forms of Chinese characters, the simplified and the complex form. The simplified Chinese characters are widely used in most parts of China, while the complex form are still used in several parts of China, namely Hong Kong, Macao and Taiwan. Some studies proposed that the complex Chinese characters are conducive to improving the learning effects, but some scholars hold opposite views. In order to further explore the role of different forms of Chinese characters in field of education, this paper studied the factors affecting the learning effects and willingness of students who use simplified Chinese characters for a long time. With the questionnaire experiment and the aliquot linear regression method, data were collected, processed and analyzed. This analysis shows the complex Chinese characters have an impact on certain students' learning effects and willingness, while some will learn better using simplified characters. These differences vary from person to person due to individual’s specific situation, which provides some suggestions to education practice.

Characteristics of summer heat stress in China during 1979‒2014: climatology and long-term trends

Heat stress describes the joint effects of high temperature and humidity. It poses severe impacts on public health and socioeconomic activities. However, its characteristics have not been fully investigated. Here we conduct a comprehensive examination of the climatological pattern and long-term trends of summer heat stress occurrences across China during 1979–2014. We find that China experienced severe heat stress conditions, particularly in densely populated and urbanized areas such as North China, the Yangtze River valley, and South China. Heat stress events in all these subregions are accompanied by decreased relative humidity (RH), and suppressed surface pressure and precipitation. Heat stress in China is mainly caused by high temperature, rather than high RH. Moreover, heat stress in most regions of China has increased noticeably during the past decades. Nationwide apparent temperature (AT, or heat index) and temperature (T) have increased by 0.37 and 0.35 °C decade−1, respectively. The yearly frequencies of cautionary, extreme cautionary, and dangerous heat stress days have increased by 0.92, 0.67, and 0.03 days decade−1, respectively. It is noticed that AT, T, and absolute humidity increase and RH decreases in most parts of China, suggesting that saturated water vapor pressure increases faster than actual water vapor pressure with rising temperature.

An intercomparison of multiple statistical downscaling methods for daily precipitation and temperature over China: present climate evaluations

In this study, we use four statistical downscaling methods to statistically downscale seven Coupled Model Intercomparison Project (CMIP5) Global Climate Models (GCMs) and project the changes in precipitation and temperature over China under RCP4.5 and RCP8.5 emission scenarios. The four statistical downscaling methods are bias-correction and spatial downscaling (BCSD), bias-correction and climate imprint (BCCI), bias correction constructed analogues with quantile mapping reordering (BCCAQ), and cumulative distribution function transform (CDF-t). Though large inter-model variability exists in the distribution and magnitude of changes in projected precipitation, particularly for wet spell length (CWD), all downscaling methods generally project a consistent enhancement of precipitation in both summer and winter over most parts of China. For the arid and semiarid Northwest China, the shortened dry spell length (CDD) is accompanied by the pronouncedly intensified very wet days (R95p), as well as the increase in maximum 5-day precipitation amount (Rx5day). In contrast, southeastern regions may experience more consecutive dry days and more severe wet precipitation extremes. The projected changes from different downscaling techniques are fairly similar for temperature, apart from the diurnal temperature range for BCSD. Warming is projected across the whole domain with larger magnitude over the north and in winter under RCP8.5. More summer days and fewer frost days would appear in the future. The bias correction components of downscaling methods cause a higher degree of agreement among models, and the downscaled results generally retain the main climate change signal of the driving models.