The study of summer rainfall characteristics in the middle of the Qilian Mountains can provide weather background support for artificial precipitation enhancement by terrain clouds. Based on hourly surface meteorological observations and Temperature of Black Body (TBB) from FY-2G satellite during 2015-2017, the characteristics of rainfall and convection in summer and relationship between diurnal variation of rainfall and local circulation are investigated. The results show that the total rainfall amount of meteorological stations with an altitude less than 3.5 km in the middle of the Qilian Mountains increases linearly with the altitude, and in the eastern part (east of 99.2°E) it changes more sharply with the altitude than that in the western part. The diurnal variation of valley wind circulation and rainfall at Yeniugou and Qilian stations in the valley is more obvious than that at Gangcha Station near the Qinghai Lake. The maximum and sub-peak of rainfall at the two stations are in the evening and early morning, respectively, corresponding to the high frequency periods of the two main topographic clouds (cumulonimbus and stracumulus) in the region, and the average rainfall intensity is 2.0-2.3 and 1.0-1.3 mm·h^-1, respectively. Compared with Zhangye Station in Hexi Corridor, the peak value of TBB probability distribution at Qilian, Yeniugou and Gangcha stations in the Qilian Mountains changed from -22--12 ℃ to -32--22 ℃ under two kinds of rainfall intensity (less than 1.5 and more than or equal to 1.5 mm·h^-1). When the threshold of TBB <-32 ℃ is used to identify rainfall cloud, the coverage rate of rainfall cloud in the Qilian Mountains is lower than that in Hexi Corridor. The threshold of TBB <-22 ℃ is more suitable for the identification of weak convective rainfall clouds in the Qilian Mountains. In the study area, the high value areas of deep and shallow convection are distributed in the direction of north-south and northwest to southeast, respectively. The diurnal variation of shallow convective frequency based on TBB data can reflect some characteristics of diurnal variation of rainfall in this region.

The warming trend of the global climate system continues, and the impact on natural ecosystems and water resources continues to rise, aggravating the already fragile global water resources. At this background, as a potential water resource, non-precipitation water (NPW) in arid area plays an important role in the maintenance of ecosystem and land surface water balance in arid area. Therefore, based on the present results of international research on NPW, the development process of NPW is summarized. The observation methods, variation characteristics, formation mechanism and the contribution of NPW to land surface water balance and its effects on crops in arid areas of Northwest China were reviewed. Finally, on the basis of combining the international frontiers, hot issues and development trends of NPW research, the shortcomings and problems of current NPW research are analyzed scientifically. It is pointed out that the study of NPW should focus on further revealing the complex formation mechanism of NPW on land surface, and strengthen the cognition of NPW in different climatic regions and different underlying surfaces. Breakthroughs have been made in key scientific issues such as the establishment of a specially targeted land surface NPW observation system, the development of the parameterization of land surface NPW in the numerical model, and the research and development of technical standards for the development and utilization of land surface NPW.

Drought is a major meteorological disaster with the highest frequency, the longest duration and the widest scope of harm in the world today, which has a huge and extensive impact on agriculture, ecology, social development and national economy all over the world. The drought is an important factor affecting agricultural production which determines the stability of crop production, further relates to the national food security. China is a large agricultural country, and also is a country with frequent drought disaster. Therefore, to improve the monitoring, forecasting and warning level of agricultural drought disaster, it is necessary to deeply understand its formation, influence characteristics, drought intensity, severity and physiological process and mechanism of crop victimization. It is also an important scientific problem to reduce and prevent drought disaster losses and improve national food security production. This paper comprehensively reviews the recent internal and overseas research progress of agricultural drought with different degrees and its impact on crop production, and explores the influence characteristics and mechanism of drought from the aspects of crop morphology, physiology, cellular and molecular levels, etc. The main indicators, indexes, methods and early warning systems in current agricultural drought monitoring are reviewed around food production to cope effectively agriculture drought. According to the new characteristics of agricultural sustainable development and drought, the current situation of drought disaster prevention and mitigation and agricultural drought coping are discussed. A series of drought coping measures both adaptation and mitigation are emphasized. On this basis, combining with the needs of national, regional and industrial development, the paper puts forward the important scientific problems, research countermeasures and the prospect of discipline development which should be emphasized in the future.

Based on the daily meteorological observation data at 17 weather stations of China and NCEP reanalysis data along the migration route of Siberian Crane during 1959-2018, the variation ranges of main meteorological elements in habitats and resting places of Siberian Crane were analyzed. Combined with the meteorological observation data at 547 weather stations in mainland of China from 1961 to 2019, the human body comfort degrees were respectively calculated and classified in habitats of Siberian Crane and mainland of China by using the human body comfort index and classification standard based on ‘the Golden Section’, and the characteristics of inner climatotherapy life during the migration of Siberian Crane were probed. The results show that the temperature in habitats and stopover places of Siberian Crane was from 0 ℃ to 15 ℃, and the relative humidity, average wind velocity and atmospheric pressure changed from 60% to 80%, 2 to 3 m·s^-1 and 1005 hPa to 1018 hPa, respectively. In general, Siberian Crane aimed to the cool, humid, breezy and clear meteorological environment, they spent 90.83% time of a year living in cool, cooler or slightly cold zones. By migrating seasonally, they stayed away from extreme cold or heat to ensure longevity, which could provide better reference for the migratory-bird sojourn of elder people in China. The human body comfort degrees in mainland of China had obvious spatial difference and seasonal complementary characteristics. The climate in Northeast China, Northwest China and part areas of Southwest China was comfortable in summer, while in coastal areas of South China and Hainan it was comfortable in winter. The periods of generalized comfort level in major cities of China could be used as a reference for the migratory-bird sojourn of the elderly. In addition, the suitable stopover could buffer the significant change of meteorological environment between the origin and destination and make the body gradually to adapt the change during the travelling to escape the heat or cold, which would effectively reduce or avoid the travelling health risks due to the wide change of meteorological environment in short period.

Dew occurs at the bottom of the atmospheric boundary layer and is affected by atmosphere, vegetation and soil. It plays an important role in arid and semi-arid terrestrial ecosystem. In view of the complexity of the physical process of land dew condensation, its observation and simulation started late. The development of dew condensation projection model has undergone three stages including statistical regression, latent heat flux relationship and simplified cloud physics/energy balance model in recent decades. The main scientific problems of dew condensation projection models are summarized: the lack of representative models caused by short observation data series, the unclear of the physical mechanism of dew formation on different underlying surfaces, the lack of effective simulation of natural underlying surface dew, the unreasonable of latent heat flux relationship of land surface models in arid and semi-arid regions. It is necessary to deepen the research on the condensation mechanism of natural underlying surface dew, reveal the influence mechanism of underlying surface properties on the condensation rate, and develop the condensation model suitable for different climatic backgrounds in China

Based on 2-meter temperature data from the second generation monthly dynamic extended range forecast (DERF2.0) model, observational temperature data at 69 weather stations in Gansu Province, reanalysis data of NCEP/DOE and sea surface temperature data of NOAA，the forecast errors of January temperature in Gansu Province by DERF2.0 model from 1992 to 2013 and their relationship with external forcing were analyzed. The results are as follows: (1) The simulated effects of January temperature by DERF2.0 model in eastern Yellow River of Gansu (known as Hedong for short) were better than that in most regions of western Yellow River of Gansu (known as Hexi for short), especially  in Gannan, Linxia, Lanzhou, Dingxi, Pingliang and Qingyang, the average errors between forecast and observation were small and stable, and the linear tendency rates of forecasted temperature in January were consistent with observation from 1992 to 2013, while the average errors were bigger and unstable in most regions of Hexi, and the change trends of forecasted temperature were contrary to actual observation. (2) Although the model could well reflect the inter-annual variation and spatial distribution pattern of January temperature in Gansu, the abnormal centers and values of temperature change were significantly different from the observation. (3) The EOF1 of error field reflected consistent overestimate or underestimate to  January temperature, the EOF2 presented an opposite distribution pattern in Hedong and Hexi, while the EOF3 appeared a reverse phase distribution pattern in Gannan Plateau and other parts of Gansu Province. (4) The main modes of forecast error field were significantly correlated with circulation and sea surface temperature (SST) in key areas, which indicated that the response of model to circulation and SST anomalies was deficient. Therefore, it was partially possible to reduce forecast errors of January temperature in Gansu by adjusting the response ability of DERF2.0 model to circulation and SST in key areas.

Based on the data of transmission line icing accidents in Northern Hebei  Province and power microweather station observations from 2012 to 2015 provided by the power company, the characteristics of spatial and temporal distribution of transmission line icing accidents were analyzed. Meanwhile, the daily minimum temperature, maximum temperature, average relative humidity, average wind speed and daily precipitation were selected as forecast factors. The risk prediction model for transmission line icing was built and verified. The results show that transmission line icing accidents mostly occurred in mountainous areas in Northern Hebei Province and mainly from November to May of the following year. Different types of underlying surfaces corresponded to different types of ice accidents. More than 56% of icing flashover occurred in plain and the plateau on bam, and dancing mainly distributed in mountains and valleys. Most accidents occurred when minimum daily temperature ranged from -8 to 0 ℃, the maximum daily temperature ranged from -4 to 4 ℃, the average daily relative humidity was above 80%, and the average daily wind speed ranged from 1 to 3 m·s-1. The test results of prediction model of transmission line icing accidents showed that when transmission line icing accidents happened, the prediction results were all above level 2, and there was no false negatives, but there was a small false alarm rate.

This article aimed to explore the law of temperature evolution and find the differences between temperature increase and heat preservation in solar greenhouses with different wall materials in order to carry out and manage greenhouse cultivation pertinently. The changes of temperature in two different materials wall solar greenhouses under different weather conditions were showed by the MATLAB programming. The sample temperature data were continuously monitored over a period of time with different gradients and orientations in both compound heterogeneous wall solar greenhouse and ordinary wall solar greenhouse. The results were as follows: (1) The temperature heating and cooling rate in compound heterogeneous wall greenhouse was faster than those of the ordinary wall greenhouse on sunny day but equal on cloudy day. It could be seen that the compound heterogeneous wall greenhouse possessed better warming performance and thermal insulating property than those of the ordinary wall greenhouse. (2) The temperature in greenhouse with compound heterogeneous wall was higher than that of the ordinary wall greenhouse, regardless of sunny day or cloudy day. On sunny day, the maximum temperature in the compound heterogeneous wall greenhouse was 3.0-8.0 ℃ higher than that in the ordinary wall greenhouse generally, and the minimum temperature in the compound heterogeneous wall greenhouse was 1.0 ℃ higher than that in the ordinary wall greenhouse. While on cloudy days, the temperature difference between maximum temperature and minimum temperature in two types of greenhouses was 2.0-3.0 ℃and 3.0 ℃, respectively.

By utilizing the global solar radiation data and precipitation observations collected in a land － atmosphere interaction field experiment
in the Badain － Jaran Desert，we explored the influencing factors of local atmospheric transmittance derived from monthly
mean diurnal variation of horizontal global solar radiation during the whole experiment． The results show that atmospheric transmittance
was enlarged by the summer precipitation with wet removal of dust aerosol， and mean atmospheric transmittance in clear days was also
increased by about 9． 0% after rainfall event，which particularly affected the global solar radiation reaching to the land surface． Moreover
comparative analysis of atmospheric transmittance before and after rainfall event show that the augment of moisture transfer from the
surface caused by evapotranspiration after rainfall event has no significant effect on atmospheric transmittance． Therefore， the summer
rainfall can lead to direct increase for atmospheric transmittance， and so solar radiation on the land surface in desert of western China
would increase．

By analyzing spectrum characteristics of snow，clouds and diferent land covers in the Qilian Mountain region based on MO-DIS data from July 2003 to March 2005，a new method for snow discrimination is presented on the basis of former researches，which combined NDSI(Normalized Diference Snow Index)and band 18，band 3 1 of MODIS to discriminate snow from clouds，saline，ice，desert，etc．with a step—by—step approach．Both result analysis and examination show that snow in the Qilian Mountain region canbe  efectively discriminated by the method of this article．