In this paper the climatic effects of waters in different natural conditions are studied according to the theoretical analysis and the observational results of twenty six waters located in various regions in China, the main conclusions are as follows: 1. Deep water has temperature increasing effect in winter and temperature decreasing effect in summer. Shallow water has temperature increasing effect all the year in general, but has temperature decreasing effect in summer in arid regions. 2. In arid regions, the misture of air over water is obviously greater than that over land. In humid regions, the air moisture above waters is generally higher than that above land, but in the rice area the mean relative humidity in all seasons and the mean vapour pressure in summer above water are probably lower than that above rice field. 3. The wind velocity at the height of 2m above water may increase by 20%～100% compared to that over land. On an average it may increase by 50%. The weaker the wind, the larger the increased percentage of the wind speed over water. 4. In the Chinese monsoon region, in general, the summer and annual precipitations in water area and off shore decrease obviously, and the winter precipitation increases somewhat, while it is exactly the reverse at the sites which are far away from waters. In the arid region, however, the precipitations on water and its neighboring area increase all the year. 5. The climatic effects of waters is more obvious when the waters are larger and deeper and the climate is dry.

本文根据我国分布在全国各地的26个湖泊、水库和河流的实际观测资料,结合理论分析,探讨了在不同自然条件下各种水域气候效应的特点和规律,并给出了其对温度、湿度、风速和降水正负影响的大致数值范围。

Land cover change affects surface radiation budget and energy balance by changing surface albedo, and further impact the regional and global climate. In this paper, the high spatial and temporal resolution remote sensing data were used to analyze the driving mechanism for surface albedo change caused by land cover change during 1990-2010. In addition, the annual scale radiative forcing caused by surface albedo changes in national 50 ecological regions were calculated to reveal the biophysical mechanisms of land cover change affecting climate change at regional scale. Results showed that during 1990-2010, the national land cover change were mainly caused by land reclamation, grassland desertification and urbanization, which were all induced by human land-use activities. Grassland and forest area decreased by 0.60% and 0.11%, respectively; while construction land and farmland area increased by 0.60% and 0.19%, respectively. The mean radiative forcing caused by land cover change during 1990-2010 was 0.062 W/m² in China, indicating a warming climate effect. However, its spatial heterogeneity was very huge in different ecological regions. Conversion of farmland to construction land, as the main type of land cover change in the Beijing-Tianjin-Tangshan urban and agricultural suburban agro-ecological region, caused an albedo reduction of 0.00456, and the maximum positive radiative forcing was 0.863 W/m² with warming climate effect. Conversion of grassland and forest to farmland, as the main type of land cover change for the Sanjiang plain temperate-humid agriculture and wetland ecological region, caused an albedo increase of 0.00152 and the maximum negative radiative forcing was 0.184 W/m² with cooling climate effect.

土地覆被变化通过改变地表反照率而影响地表辐射收支与能量平衡,从而对区域和全球气候产生影响。本文利用高时空分辨率遥感数据分析1990-2010 年中国土地覆被变化改变地表反照率的时空驱动机制,并计算全国50 个生态区地表反照率变化导致的年际尺度辐射强迫,揭示土地覆被变化在生态区尺度上影响气候变化的生物地球物理机制。结果表明:1990-2010 年全国土地覆被变化以耕地开垦、草地沙化、城市化等人类土地利用活动导致的土地覆被变化最为明显,全国草地与林地面积分别减少了0.60%和0.11%;建设用地和耕地面积分别增加了0.60%和0.19%。全国土地覆被变化通过改变地表反照率引起的平均辐射强迫为0.062 W/m²,表现为增温的气候效应,但在生态区尺度辐射强迫空间差异很大。京津唐城镇与农城郊农业生态区主要土地覆被变化为耕地转为建设用地,引起地表反照率降低了0.00456,产生0.863 W/m²的辐射强迫,表现为增温的气候效应;而三江平原温带湿润农业与湿地生态区主要的土地覆被变化为林草地转为耕地,引起地表反照率升高了0.00152,产生-0.184 W/m²的辐射强迫,表现为降温的气候效应。

Traditional methods for estimating evapotranspiration are mostly based on local scales. For data-scarce basins where ecological hydrology has undergone dramatic changes, a land surface process model that fully considers the spatial variability of the underlying surface of the watershed provides a new method of performing continuous actual evapotranspiration simulations over a long time series and at a large scale. Taking the Ebinur Lake basin as the research area, the variable infiltration capacity (VIC-3L) model was used to simulate the hydrological processes from 1960 to 2017 and explore the spatial and temporal variations in actual evapotranspiration in the study area. Additionally, the wavelet analysis method was used to analyze the multiscale characteristics of the five meteorological elements and the simulated values of actual evapotranspiration in the study area. The following results were obtained: (1) The runoff Nash-Sutcliffe efficiency (NSE) coefficients of the VIC at the Wenquan and Bole stations were 0.09 and 0.23, respectively, and the simulation results were satisfactory. Specifically, the simulated value and theoretical calculated value of the actual evapotranspiration of the VIC had an R2 value of 0.80, an RMSE of 31.76 mm a-1, an NSE of 0.32, and a relatively good simulation effect. (2) Regarding the time scale, the interannual actual evapotranspiration has presented an upward trend over the past 58 years, with the annual average actual evapotranspiration increasing at a rate of 1.03 mm a-1. Furthermore, both monthly and daily evapotranspiration showed a single peak trend. Regarding the interdecadal changes, the actual evapotranspiration from May to July showed a downward trend in the 1990s and in the early 21st century, and an upward trend in the 1970s, while no significant change in tother months. (3) In terms of spatial distribution, the actual evapotranspiration generally showed strong evapotranspiration in high altitude areas and their surroundings. From spring to summer, the area with strong evapotranspiration shifted from the northwest to southeast. The spatial distribution of annual actual evapotranspiration is consistent with that in spring and summer. (4) A wavelet analysis identified 1 to 4 significant periods in the time-frequency domain for the actual evapotranspiration and meteorological elements in the study basin. Over a certain period, the average wind speed, average temperature, and sunshine hours changed ahead of the actual evapotranspiration while the annual precipitation and relative temperature lagged behind the actual evapotranspiration changes. Affected by precipitation, the actual evapotranspiration had a "strong-weak" transition in 1965 and 2003 with a period of 1 a; and affected by relative humidity, the actual evapotranspiration had a "strong-weak" transition in 1965 and 2008 with a period of 2-4.5 a.

传统估算蒸散发的方法大都基于局地尺度,而在生态水文发生剧烈变化的资料稀缺流域背景下,充分考虑流域下垫面的空间变异性的陆面过程模型为流域长时序、大尺度及连续模拟实际蒸散量提供了新途径。以艾比湖流域为研究区,应用可变下渗能力模型（VIC）模拟1960—2017年艾比湖流域的水文过程,探讨研究区值实际蒸散发量的年、月、日时空变化规律,并运用小波分析方法对5个气象要素及研究区实际蒸散发量的模拟值进行多尺度特征分析,结果表明：① VIC在温泉和博乐的径流纳什效率系数（NSE）分别为0.09和0.23,模拟效果较为满意;VIC实际蒸散量的模拟值与理论计算值,R²达0.80,均方根误差（RMSE）为31.76 mm a^-1,NSE为0.32,模拟效果相对较好;② 时间尺度上,艾比湖流域58 a来年际实际蒸散量呈上升趋势,年均实际蒸散量以1.03 mm a^-1的速率递增;月值和日值蒸散量均呈单峰趋势;且年代际变化中5—7月的实际蒸散量在20世纪90年代和21世纪呈现下降趋势,20世纪70年呈现上升趋势,而其余月份无明显变化;③ 空间分布上,艾比湖流域内实际蒸散发量总体上呈现高海拔及其附近地区蒸散强烈,从春季到夏季,强蒸散区由西北向东南转移,年实际蒸散量空间分布与春夏季分布一致;④ 艾比湖流域实际蒸散发量与各气象要素在时频域中均存在1~4个显著性周期,且在一定尺度的周期上,平均风速、平均温度以及日照时数超前于实际蒸散量变化,而年降水量和相对湿度滞后于实际蒸散量变化,受降水影响实际蒸散发1965年和2003年发生1 a周期的“强—弱”转换,受相对湿度影响实际蒸散量在1965年和2008年发生2~4.5 a周期的“强—弱”转换。

As a link between the atmosphere and the geosphere, the hydrological cycle is affected by both climate change and Land Use/Cover Change (LUCC). However, most existing research on runoff response focused mainly on the impact of the projected climate variation, neglecting the influence of future LUCC variability. Therefore, the objective of this study is to examine the co-impacts of both projected climate change and LUCC on runoff generation. Firstly, the future climate scenarios under BCC-CSM1.1 and BNU-ESM are both downscaled and corrected by the Daily Bias Correction (DBC) model. Secondly, the LUCC scenarios are predicted based on the Cellular Automaton-Markov (CA-Markov) model. Finally, the Soil and Water Assessment Tool (SWAT) model is used to simulate the hydrological process under different combinations of climate and LUCC scenarios, with the attempt to quantitatively evaluate the impacts of climate change and LUCC on runoff generation. In this study, the Hanjiang River basin is used as the case study area. The results show that: (1) compared with the base period (1966-2005), the annual rainfall, daily maximum and minimum air temperatures during 2021-2060 will have an increase of 4.0%, 1.8 ℃, 1.6 ℃ in RCP4.5 scenario, respectively, while 3.7%, 2.5 ℃, 2.3 ℃ in RCP8.5 scenario, respectively. (2) During 2010-2050, the area proportions of forest land and construction land in the study area will increase by 2.8% and 1.2%, respectively, while those of farmland and grassland will decrease by 1.5% and 2.5%, respectively. (3) Compared with the single climate change or LUCC scenario, the variation range of future runoff under both climate and LUCC is the largest, and the influence of climate change on future runoff is significantly greater than that of LUCC. This study is helpful to maintain the future water resources planning and management of the Hanjiang River basin under future climate and LUCC scenarios.

作为联结大气圈和地圈的纽带,水文循环同时承受气候变化和土地利用/覆被变化（LUCC）的双重影响,然而大多数的水文响应研究主要关注未来气候变化对径流的影响,忽略了未来LUCC的作用。因此,本文的研究目的是评估未来气候变化和LUCC对径流的共同影响。首先采用2种全球气候模式（BCC-CSM1.1和BNU-ESM）输出,基于DBC降尺度模型得到未来气候变化情景;然后,利用CA-Markov模型预测未来LUCC情景;最后,通过设置不同的气候和LUCC情景组合,采用SWAT模型模拟汉江流域的未来径流过程,定量评估气候变化和LUCC对径流的影响。结果表明：① 未来时期汉江流域的年降水量、日最高、最低气温相较于基准期（1966—2005年）,在RCP 4.5和RCP 8.5浓度路径下,分别增加4.0%、1.8 ℃、1.6 ℃和3.7%、2.5 ℃、2.3 ℃;② 2010—2050年间,流域内林地和建设用地的面积占比将分别增加2.8%和1.2%,而耕地和草地面积占比将分别减少1.5%和2.5%;③ 与单一气候变化或LUCC情景相比,气候变化和LUCC共同影响下的径流变化幅度最大,在RCP 4.5和RCP 8.5浓度路径下未来时期年平均径流分别增加5.10%、2.67%,且气候变化对径流的影响显著大于LUCC。本文的研究结果将有助于维护未来气候变化和LUCC共同影响下汉江流域的水资源规划与管理。

The weather research and forecasting model including a one-dimensional thermal diffusion lake model is adopted to investigate the summer climatic effect of the lake clusters over Tibetan Plateau (TP) during 2008-2014 based on two experiments with and without the lakes. Overall, the model can reasonably reproduce the daily variations of lake surface temperature and the spatial patterns of 2 m air temperature (T-2m) and precipitation over TP during summer. Sensitivity results show that the effects of TP lakes on the over-lake T-2m and precipitation exhibit distinctive seasonal and diurnal features and strong space dependence. Generally, the TP lakes tend to cool the local T-2m and enhance the precipitation over the lake and surrounding areas. With the summer advances, the cooling effect of TP lakes weakens while the lake-induced enhancement of precipitation becomes more evident. During daytime, the TP lakes decrease the T-2m and suppress the short-duration (<= 6 h) rainfall in afternoon. However, the TP lakes increase the T-2m and strengthen the convective rainfall over the lake and surrounding areas by simultaneously enhancing both short and long-duration (>6 h) precipitation during nighttime. The lakes over the southeastern central TP (CTP) lead to slight warming and pronounced precipitation increases, while the other lakes in CTP mainly cause significant cooling and suppressed precipitation. Such opposite effects are mainly because the lakes over the western and northeastern CTP hardly produce nighttime warming and the associated circulation changes favorable for the convective precipitation as found over the southeastern CTP, suggesting that the climate effects of TP lakes may be modulated by the lake intrinsic features, local terrain distributions, and background atmospheric circulations.

There exists lake-land breeze that wind blowing onshore from lake to land during the day and offshore in the evening around lake area, due to differences in air pressure mainly caused by different heat capacities between lake and land. Generally speaking, the closer to the lake, the more remarkable the lake climate effects. For studying the lake climate effects, it is not only important for understanding the characteristics of local climate and atmospheric circulation, but also helpful for analyzing and forecasting meso-and micro-scale weather processes. Miyun Reservoir (MYR), which located at 15 km north of Miyun District of Beijing city, is the largest artificial lake in North China. Up to now, there are seldom reports on the influence of MYR on local weather and climate. Based on hourly observation data obtained by 77 automatic weather stations surrounding MYR from 2011 to 2015, local climate effects of MYR were explored and discussed in the present work. The results showed that: 1) comparing with peripheral plains, climate effects of MYR were characterized by the facts that lower air temperature, higher humidity, slightly weaker wind speed and larger rainfall. As far as regional climate was concerned, the MYR had a modulate effect on the local climate and the spatial extent of the effect is about 10 km. The closer to the MYR, the more notable the MYR climate effects. 2) The MYR climate effects were mainly occurred in the summer, especially for temperature and rainfall. In detail, averaged air temperature was lower of 0.96℃ and averaged rainfall amount was higher of 13.3% in MYR than in the adjacent plains, where has the same elevation with MYR away from 10km. In addition, there were significant differences in diurnal variations of meteorological factors between the south and north regions of the MYR. 3) Excluding the impact of the large-scale background wind field, local wind presented the characteristics of monthly variation, i.e., mountain breeze was dominant from April to September, especially in summer; while in other months, valley breeze was more prevailing, especially in the wintertime. In general, annual averaged local wind speed was about 0.14 m/s in the east-west direction, which was slightly larger than that of 0.10 m/s in the north-south direction around the MYR. 4) In summer, there existed significant differences in wind vectors at the south and north regions of the MYR, due to the influence of local circulation. In most time of the whole day, component anomalies were usually in the same phase, while component anomalies presented out of phase at the south and north regions of the MYR. Lake-land breeze and mountain-valley breeze had the same/opposite directions at the north/south regions of the MYR, and thus these correspondingly formed the overlaying/counteractive effects. Due to lake-land differences in heat capacities and topography effects, lake-land breeze and mountain-valley breeze in the areas around MYR usually existed at the same time, which mainly caused the differences in seasonal and diurnal variations of meteorological elements at different locations around the MYR region.

应用近5 a自动气象站观测资料,分析了华北地区最大人工湖——密云水库的局地气候效应。结果表明：① 密云水库库区相比于附近平原地带具有气温偏低、湿度偏高、风速偏弱、降水量偏大等特点。水库对区域气候的影响范围约在10 km内,离水库越近的地方,受影响越大。② 密云水库的气候效应主要体现在夏半年,尤以气温和降水最为明显。③ 水库南、北两侧受到的局地环流的影响具有明显的差异,库区东西方向的年平均局地风速约为0.14 m/s,南北方向约为 0.10 m/s。下垫面属性的热力差异及特殊地形条件使得密云水库附近同时存在山谷风和湖陆风现象,其叠加效应是导致区域内不同位置间气象要素出现季节性及日变化差异的主要原因。

The urban heat island (UHI), the phenomenon of higher temperatures in urban land than the surrounding rural land, is commonly attributed to changes in biophysical properties of the land surface associated with urbanization. Here we provide evidence for a long-held hypothesis that the biogeochemical effect of urban aerosol or haze pollution is also a contributor to the UHI. Our results are based on satellite observations and urban climate model calculations. We find that a significant factor controlling the nighttime surface UHI across China is the urban-rural difference in the haze pollution level. The average haze contribution to the nighttime surface UHI is 0.7 +/- 0.3 K (mean +/- 1 s.e.) for semi-arid cities, which is stronger than that in the humid climate due to a stronger longwave radiative forcing of coarser aerosols. Mitigation of haze pollution therefore provides a co-benefit of reducing heat stress on urban residents.

Environmental health research employs a variety of metrics to measure heat exposure, both to directly study the health effects of outdoor temperature and to control for temperature in studies of other environmental exposures, including air pollution. To measure heat exposure, environmental health studies often use heat index, which incorporates both air temperature and moisture. However, the method of calculating heat index varies across environmental studies, which could mean that studies using different algorithms to calculate heat index may not be comparable.We investigated 21 separate heat index algorithms found in the literature to determine a) whether different algorithms generate heat index values that are consistent with the theoretical concepts of apparent temperature and b) whether different algorithms generate similar heat index values.Although environmental studies differ in how they calculate heat index values, most studies' heat index algorithms generate values consistent with apparent temperature. Additionally, most different algorithms generate closely correlated heat index values. However, a few algorithms are potentially problematic, especially in certain weather conditions (e.g., very low relative humidity, cold weather). To aid environmental health researchers, we have created open-source software in R to calculate the heat index using the U.S. National Weather Service's algorithm.We identified 21 separate heat index algorithms used in environmental research. Our analysis demonstrated that methods to calculate heat index are inconsistent across studies. Careful choice of a heat index algorithm can help ensure reproducible and consistent environmental health research.