In order to make an in-depth study of urban thermal environment of Zhengzhou, the temporal evolution and spatial distribution characteristics of urban heat island effect are analyzed based on the MODIS land surface temperature product (MYD21A1), and the causes and driving mechanism of urban heat island effect are discussed from both natural and anthropogenic factors in combination with the data of land use/land cover types and Zhengzhou statistical yearbooks. The results show that there is no significant difference in the spatial distribution of annual mean heat island intensity between day and night in Zhengzhou, and the areas with stronger heat island intensity or above are mainly in the main urban area. The temporal variation of heat island effect in Zhengzhou has diurnal and seasonal differences. During the daytime, the proportion of heat island area increased insignificantly in spring and significantly in summer, and decreased insignificantly in autumn and winter. In spring, summer and autumn, the proportion of heat island area at night increased insignificantly, while in winter, the heat island effect was weak and there was no obvious change characteristics. The inter-annual variation of urban heat island proportion index of Zhengzhou was consistent with heat island intensity. The urban heat island proportion index during daytime and nighttime was higher in summer, then in spring, autumn and winter in turn. The heat island effect of different land use/land cover types was obviously different, with the highest in urban and rural building land, followed by cultivated land, and the lowest in woodland and water area. There is a negative correlation between vegetation coverage and land surface temperature. Solar radiation intensity has a positive driving effect on urban heat island effect, and population density, GDP and built-up area are all positively correlated with urban land surface temperature.

Based on the groundbased 3D lightning detection network (3D LDN) data in Dalian and Qingdao areas, the detection efficiency of FY-4A lightning mapping imager (LMI) in the Yellow sea and Bohai sea area was evaluated. It was found that from the four severe convective weather processes in Dalian area in 2019, most of the lightning pulses occurred within radar echoes intensity greater than 30 dBZ, and the corresponding cloud top height was about 9 km, the number of groups detected by FY4A LMI was fewer than that of the pulses presented by groundbased 3D LDN, the average ratio was 0.2, ranging from 0.15 to 0.26. From the five severe convective weather processes in Qingdao area in 2019, the number of groups detected by FY4A LMI was also fewer than that of the pulses presented by groundbased 3D LDN, the average ratio was 0.34, ranging from 0.27 to 0.4. Generally, the lightning pulses location detected by FY-4A LMI was consistent with the lightning pulses presented by groundbased 3D LDN in Qingdao area, which located in strong echo area. However, the detection efficiency of FY4A LMI in the Yellow Sea and Bohai Sea area was lower.

Based on the hourly precipitation observation data of 105 national stations and 1240 regional stations and 8 Doppler weather radars data in Xinjiang from 2010 to 2018, from the perspective of operational forecasting, the definition of shortterm heavy precipitation process in Xinjiang was proposed and 468 shortterm heavy precipitation processes were selected, and circulation configuration of influence system and radar observation characteristics were analyzed. The results show that there were four kinds of influence systems including the central Asia trough (vortex), the west Siberian trough (vortex) and low level northwest jet stream. The convective storms resulting in shortterm heavy rainfall were combined enhancement type, train effect type and isolated convective cell type, and the combined enhancement type was 45.1%, isolated convective cell type was 34.8%, and the train effect type was 20.2%, respectively. The parameter thresholds of the maximum reflectivity factor intensity (Zmax), the maximum height of the strong echo (Dmax), the maximum height of the echo top (ET) and the maximum vertical accumulated liquid water content (VIL) observed by Doppler radar during shortterm heavy precipitation processes in southern Xinjiang were less than those in northern Xinjiang, and in Yili prefecture they were largest and in Aksu they were smallest. The shortterm heavy precipitation in Yili prefecture was dominated by low centroid echo, while in other regions it was dominated by low centroid and high centroid echo.

Based on 0 cm and 20 cm monthly average ground temperature and air temperature from 68 meteorological stations in Zhejiang Province from 1951 to 2018, and the annual average temperature for one hundred years at Hangzhou and Wenzhou stations, the 0 cm and 20 cm annual average ground temperature in Zhejiang Province from 1905 to 2018 were established by using the method of global correction of local station observations (GAoSV). The spatialtemporal characteristics of ground temperature at a century scale were analyzed through Morlet wavelet analysis, MK test and other climatic statistical diagnosis methods. The results are as follows: (1) The climate tendency rate of 0 cm and 20 cm ground temperature in Zhejiang was 0.2 ℃·（10 a）-1 (P＜0.05) from 1905 to 2018. The highest, lowest and average value was 20.5,16.5 and 18.6 ℃ at a depth of  0 cm, and 19.9, 16.1 and 18.1 ℃ at a depth of 20 cm, respectively. (2) Under the background of climate warming, the ground temperature in Zhejiang Province experienced a “coldwarm” climate evolution, and the ground temperature was lower before the mid1990s and higher after that. Two obvious rising stages were during 1905-1925 and 1991-2018, respectively. (3) The spatial distribution of 0 cm and 20 cm annual average ground temperature in Zhejiang Province showed the same spatial distribution characteristics with low in the north and high in the south. The high value areas were distributed in Wencheng, Longquan, Lishui and the south of Wenling, while the low value areas were distributed in Anji, Xiaoshan, Deqing, Huzhou, Changxing. (4) Obvious oscillation periods of 2-6 years, 6-8 years and 16-20 years in different periods were detected through analyzing annual average ground temperature of 0 cm and 20 cm in Zhejiang Province from 1905 to 2018, and the abrupt point occurred around 1986.

Based on daily meteorological observation data in main apple producing areas of China from 1971 to 2017, the crop coefficients at different growth stages of apple were corrected, firstly. And on this basis the precipitation suitability model at each growth stage of apple was constructed. Then, combined with the geographical distribution of apple in advantageous areas, the threshold of precipitation suitability of apple, and the spatial and temporal distribution characteristics of precipitation suitability at each growth stage of apple were analyzed. Furthermore, the temporal and spatial anomalies were discussed by using empirical orthogonal function (EOF) decomposition method. The results are as follows: (1) The thresholds of precipitation suitability at initial growth stage, vigorous growth stage and later growth stage of apple were 0.30-1.29, 0.63-1.78 and 0.62-2.84, respectively. The areas within the threshold range at each growth stage of apple accounted for 94.8%, 94.7% and 95.9% of main producing areas, respectively. The change trend of precipitation suitability in most regions at three growth stages of apple wasn’t significant from 1971 to 2017. (2) The variance contribution rates of the first eigenvector field of precipitation suitability at initial growth stage and vigorous growth stage of apple were 50.53% and 32.26%, respectively. The eigenvalues were almost positive in the whole region, which indicated that the spatial change of precipitation suitability had good consistency, and the oscillation intensity of precipitation suitability strengthened from northeast and southwest to the middle. The variance contribution rate of the first eigenvector field of precipitation suitability reached 49.51% at later growth period, and the distribution pattern in Liaoning Province and the local part of eastern Hebei Province was opposite to other areas. (3) The second eigenvector field of precipitation suitability appeared an opposite phase distribution pattern in the east and the west at initial growth period of apple, while that were anti-phase distribution pattern in northern and southern parts at vigorous growth period and later growth period of apple. 

Based on  daily rainfall  from 34 national  meteorological observation stations in the Hetao area , Inner Mongolia during 1961-2018, extreme precipitation events and extreme precipitation processes were analyzed in the past 58 years. Atmospheric circulation features of typical extreme precipitation processes were aslo analyzed. The main results are as follows: (1) Average annual precipitation decreased from southeast to  northwest, and precipitation was rich from July to August. The precipitation decreased significantly in August and increased significantly in May, June and December. (2) The thresholds of extreme precipitation became lower from southeast to  northwest, the historical maximum extremum occurred in Wushenzhao  of Ordos,  the historical minimum extremum occurred in Hailisu of Bayannur. The frequency of extreme precipitation events was more than five times in most areas, the intensity became weaker from southeast to northwest. (3) The extreme precipitation events was most from July to August, and its intensity was strongest in August. The frequency of extreme precipitation events and the intensity increased significantly in September. (4) The annual average extreme precipitation process intensity decreased significantly, the process precipitation was concentrated in Tumote Zuo Banner, Ejin Horo Banner and the city of Huhhot. (5) The extreme precipitation processes were influenced by the southwest flow at the front of trough, and the plentiful vapor and exceptionally strong updraft flow could easily cause extreme precipitation events.

Based on the observation data during the period of the experiment with ‘theoretical study and observations of water and energy exchange and planetary boundary layer on inhomogeneous underlying surface in oasis system’, the influences of surface temperature difference between desert and oasis, buoyancy frequency (Brunt-Visl frequency) and background wind velocity on oasis effect were discussed by a series of idealized numerical tests of BLASIUS (boundary layer above stationary, inhomogeneous uneven surface) model with high resolution and complex terrain. The results show that the cold island effect and humid island effect enhanced with the increase of surface temperature difference between oasis and desert, and the enhancing action mainly occurred below 500 m over the ground. The horizontal range of ‘cold island’ over oasis enlarged and the vertical height of ‘humid island’ decreased with increase of surface temperature difference. The influence on ‘humid island effect’ was about an hour later than that on ‘cold island effect’. The updraft airflow over the oasis increased and the vertical velocity increased over the transition area above 1.5 km height with increase of buoyancy frequency. The symmetry of vertical circulation between oasis and desert decreased with increase of initial background wind speed, and the height of circulation center decreased and the strength weakened.

The great natural disaster of a rare hail, tornado occurred in Funing of Jiangsu Province on 23 June 2016. It caused huge economic losses and casualties. Based on the observed data from Doppler radar (SA) in Yancheng, this process was analyzed, and then compared with the strong convective weather in Xingtai on 12 May 2018.The results show that the Funing tornado occurred at the right side of the 200 hPa high-altitude jet stream exit. It was controlled by the strong southwest warm and wet airflow at the front of the 500 hPa trough. There were dry cold air in the middle layer and obvious shear in lower layer. Its environmental field had strong convective available potential energy (CAPE), vertical wind shear (WSR) and lower height of uplift condensation（LCL）. Before the Funing tornado, the maximum reflectivity factor (Zmax), strong echo center height (HT), echo top height (TOP) continued to increase, the vertically integrated liquid water content (VIL) surged. In the 2 volume sweeps before the tornado, HT and VIL felled sharply. There was an obvious three-body scattering phenomenon in Funing tornado, which was an indication for early warning of hail. Funing tornado storm had the characteristics of hook echo and strong mesocyclone of classic super cell, accompanied by TVS. It was a huge disaster caused by huge super cell storm. Compared with the hail wind process in Xingtai, the storm parameters of Funing tornado at its vigorous stage were obviously larger than those of the latter.

Drought is the most severe natural hazard affecting on human society and it exists generally in the whole global. In recent a century, the climate warming and society developing exacerbated the degree of drought influence and risk, which brought a great threat to global agriculture, water resource, ecological environment security and society sustainable development. It is the basis of fighting and managing drought and reducing drought vulnerability to improve the drought monitoring and early warning skill. In this paper, we introduce the new progress of drought monitoring and prediction operation and research in the United States in recent years, and provide an overview of the development of regional and global drought monitoring and prediction systems (DMAPS). It focuses on the scientific researches and technology improvement of drought. At last, the opportunities and challenges of drought monitoring and prediction are discussed referring to NOAA Interagency Drought task Force in 2016, which is beneficial to provide a new perspective for drought monitoring and forecast in China.

Based on daily p recip itation data from 82 meteorological stations in Shandong Province from 1961 to 2004, the annual p recipitation and rainy dayswith different gradeswere calculated. The long - term variation and abrup t change characteristic of annual p recipitation and rainy dayswith different gradeswere analyzed by using accumulative anomaly and T - test, and the response of drought disaster to variation of p recip itation and rainy dayswere analyzed also. The results are as follows: The abrup t change of annual p recip itation, rainy days with moderate and above rainfall and drought disaster area occurred in the middle 1970 s, but rainy dayswith little and small rainfall aswell as total rainy days appeared in 1988 under the globalwarming background. After the abrup t change, the years appeared frequently with anomaly decrease of annual rainfall and rainy days, while the strong rainy days increased obviously. Precip itation and rainy dayswith different grades have a much closer negative correlation with drought disaster area. Abnormal decreases of annual precip itation and rainy days enlarged the drought area in Shandong Province.

This paper analyzed the continuous detecting data ofLanzhou CINRAD /CC Radar abouta hailprocess occurred in Dingxi on July 18, 2008, summarized themain characteristics of the radarproducts during this hailprocess such as reflectivity, radial velocity,RCS vertical section, vertical integrated liquid content and so on. Then it discussed the detection methods for monitoring hail by DopplerRadar, found out the typical echo characteristic of supercell storms such as hook echo, bounded weak echo region(BWER),echowal,l suspended echo, obvious influx nick, existingmesocyclone etc., and summed up some informationwhich are good fornowcasting ofhai,l such as severe change ofVIL, corresponding relationship ofET and hailprocess, obvious three-body scatter characteristic and so on, these information will be of great value for us to detect severeweather events by radar.

Based on monthly temperature, sea surface temperature over Pacific, 500 hPa geopotential height field and circulation data in July and August from 53 stations in Northeast China during 1961 - 2004, the temporal and spatial temperature pattern over Northeast China from July to August in recent 44 yearswas analyzed using Emp iricalOrthogonal Function ( EOF) analysismethod. The canonical correlation analysis (CCA) method was used to forecast and testmonthly temperature in midsummer. Results show that the spatial pattern ofmonthly temperature in July and August ismainly classified into three types: the whole region consistency, north - south type and east - west type. The CCA method handles better in p rediction of monthly temperature in July and August of 2005 and 2006 in Northeast China.