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Characteristicsof cloud macroscopic parameters in the hinterland of Taklimakan Desert in arid region of Northwest China in August and September 2019
LI Zhengpeng, BI Jianrong, ZUO Dapeng, ZHANG Linhan, YANG Fan
Journal of Arid Meteorology    2022, 40 (4): 567-576.   DOI: 10.11755/j.issn.1006-7639(2022)-04-0567
Abstract389)   HTML14)    PDF(pc) (19145KB)(1033)       Save

Cloud is a key modulator of the energy budget in earth-atmosphere system. The macro- and micro-physical parameters of cloud have an important influence on precipitation intensity and distributions in arid region. In order to clarify the macroscopic characteristics of cloud in the hinterland of Taklimakan Desert (TD), the structures of cloud layers were continuously detected at Tazhong station from July 23 to September 30 in 2019 by using the CHM15K ceilometer. The variation characteristics of cloud base height, cloud layer thickness, and total cloud coverage were analyzed over Tazhong station in August and September 2019. The results show that the ceilometer could clearly observe the distributions of cloud layer and rainfall processes over TD. The average cloud base height at Tazhong station was about 4.6 km in August and September 2019.The high and middle level clouds predominated at Tazhong station. And the sum of proportions of high and middle level clouds exceeded 90% in August and September, and the proportion of single-layer cloud was significantly higher than that of multi-layer cloud. The cloud layer thickness at Tazhong station was relatively small, the average thicknesses of the first cloud layer were 402 m and 532 m in August and September, respectively, corresponding cloud layer thickness less than 500 m accounted for 64.2% and 58.8%. This implied that the cloud layers were geometrically thin at Tazhong station in August and September 2019. The results of total cloud coverage indicated that the proportion of all-sky cloud day in August was highest (32.6%), whereas the proportion of cloudless sky in September was highest (40.8%), which suggested that clear-sky days were dominant in September. The results of this study will help to understand the spatial and temporal distributions and evolution features of cloud macroscopic characteristics over the hinterland of TD, which provide invaluable datasets for validation of numerical model simulations and satellite remote sensing products.

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Grassland soil respiration characteristics and their influencing factors in semi-arid region of Loess Plateau during the growing season in 2020
ZHANG Linhan, BI Jianrong, ZHANG Xueteng, LI Zhengpeng, ZHAO Changming, MA Xiaojun
Journal of Arid Meteorology    2022, 40 (3): 354-363.   DOI: 10.11755/j.issn.1006-7639(2022)-03-0354
Abstract503)   HTML18)    PDF(pc) (11276KB)(1303)       Save

The automated soil CO2/gas flux system (model LI-8100A) was used to continuously observe the soil respiration rate, soil temperature and water content in a semi-arid grassland of Loess Plateau during the growing season (from May to October). The temporal variations of soil respiration were comprehensively analyzed, and the influences of environmental hydrothermal factors on soil respiration were studied. The results are as follows: (1) The diurnal dynamic variations of soil respiration rate were significantly different under diverse weather conditions, and the daily mean value (2.90 µmol·m-2·s-1) and variation range (1.73-4.92 µmol·m-2·s-1) on sunny days were obviously greater than those on cloudy and overcast days. The average diurnal variations of soil respiration rate in different months all showed a significant unimodal pattern, with the maximum (2.20-4.40 µmol·m-2·s-1) appearing at 12:00 BST or 13:00 BST and the minimum (0.71-1.70 µmol·m-2·s-1) appearing at 05:00 BST or 06:00 BST. The daily mean values were close to the observed values at 10:00 BST or 19:00 BST. (2) The soil respiration rate in both daytime and nighttime were low in May and June, and increased gradually from June, then reached the peak value (in daytime 3.31±0.98 µmol·m-2·s-1, in nighttime 1.80±0.39 µmol·m-2·s-1) in August, afterwards gradually decreased. Furthermore, the lowest value occurred in October (in daytime 1.55±0.55 µmol·m-2·s-1, in nighttime 0.81±0.12 µmol·m-2·s-1), and soil respiration rates in daytime were always higher than those in nighttime. The nocturnal soil respiration contributed 27.2%-32.4% to the total respiration during the whole growing season. Therefore, the effects of nocturnal soil respiration should be considered in the current carbon cycle models of grassland ecosystem. (3) Soil temperature was the main environmental factor affecting soil respiration rate, but the univariate model of soil temperature was not enough to fully explain the diurnal dynamic changes of soil respiration. The bivariate nonlinear model combined with soil temperature and water content could be better fitted the soil respiration rate and accounted for 74.0% of the variation. (4) The temperature sensitivity indices (Q10) of the entire day, daytime, and nighttime throughout the growing season in 2020 varied from 1.38 to 2.14, from 1.22 to 1.96, and from 0.85 to 1.64, respectively, with the corresponding mean values of 1.58±0.23, 1.41±0.19 and 1.20±0.16. This suggested that replacing the daily mean values of Q10 with daytime averages would result in an underestimation of about 10.8%.

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Construction of Ground Temperature Series and Its Characteristics from 1905 to 2018 in Zhejiang Province
XIAO Jingjing, MA Hao, ZHANG Yuhui, HE Zhonghua, LI Na, WEN Quanpei, LI Zhengquan
Journal of Arid Meteorology    2021, 39 (3): 386-393.  
Abstract351)      PDF(pc) (2445KB)(1543)       Save
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.
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Design and Implementation of the On -line Displaying System Associated with the Extended - range Synoptic Processes Forecast
MA Hao,FAN Gaofeng,LI Zhengquan,MAO Yuding,LEI Yuan
Journal of Arid Meteorology    2015, 33 (1): 167-173.   DOI: 10. 11755 / j. issn. 1006 - 7639( 2015)- 01 - 0167
Abstract1399)      PDF(pc) (2452KB)(2002)       Save

Recently,frequent occurrence of extreme weather and climate events had caused serious impacts on people s production and livelihood,so the extended - range weather forecast attracted more and more attention. With the national spread and promotion of the low - frequency synoptic chart,extended - range synoptic processes forecast was developing vigorously throughout the country. To better satisfy the service need of synoptic processes forecast,an on - line displaying system associated with the extended - range synoptic processes forecast was developed in Zhejiang Climate Center. In this paper,the design philosophy,detailed structure,and the thoughts of future improvement and optimization were introduced extensively. The on - line displaying system included two columns,i. e. ,the heavy rainfall processes and the intensive air - temperature reduction processes based on different objects of forecast. The column of heavy rainfall processes consisted of the figure comparing between forecast and the actual state,forecast document,table of dynamic scores,table of brief description of the realistic observation,and table of detailed description of the realistic observation. The contents of intensive air - temperature reduction processes column were similar to that of the heavy rainfall processes,but the table of dynamic scores was omitted. In the future,the system will receive more improvement and optimization through designing more suitable indices and establishing the marking scheme for intensive air - temperature reduction processes and expanding the components of extended-range synoptic processes forecast.

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Modification of CI Comprehensive Meteorological Drought Index and Its Application in Ningxia
WANG Suyan,ZHENG Guangfen,LI Xin,LI Zhenglin,YANG Jianling,FENG Jianmin
Journal of Arid Meteorology    DOI: 10. 11755/j. issn. 1006 -7639(2013) -03 -0561
Study on Relationship Between Lightning Activity and Atmospheric Instability Parameters in Lanzhou and Hangzhou Areas
LIU Yan, LI Zheng, KANG Feng-Qin
J4    2010, 28 (2): 142-147.  
Abstract1421)      PDF(pc) (1007KB)(1764)       Save

 Based on the cloud-to-ground flashes data obtained by lightning location system from Gansu and Zhejiang, the temporal and spatial distrbution features of lightning activities have been analyzed respectively. In addition, by using ground and sounding data in lightning activity processes, the ralationship between lightning activity and atmospheric instability parameters is analyzed in the paper. The results indicated that the relative humidity of surface, SI, convective available potential energy(CAPE) and convective inhibition energy(CIN) were all impact factors of lightning activities, but the CIN has a greater impact on the lightning activities in Hangzhou and the relative humidity of the surface play a decisive role in Lanzhou.

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