Search

The co-variability in the summer precipitation and cloud-to-ground lightning over South China, where climatological lighting and precipitation frequently occur (105～122 ° E, 20～35 ° N), has been examined using the ADTD lightning location network and precipitation data merged ground-gauge, satellite, and radar. The coupling self-organizing map (SOM) has been applied to the daily flash density and precipitation anomalies from 2016 to 2021. It turns out that there are five clusters associate with the co-variability in the flash density and precipitation over South China. Specifically, the first (fifth) cluster is characterized by a dipole pattern with enhanced rainfall / increased lightning activity (suppressed rainfall / decreased lightning activity) over the Yangtze-Huai River valley and suppressed rainfall/decreased lightning activity (enhanced rainfall/increased lightning activity) over the southern part of South China. The tightest lightning-precipitation coincidence is observed in the first and fifth clusters. Results obtained from SOM exhibit large non-linearity and asymmetry of the relationship between the regional lightning and precipitation anomalies over South China. Further examinations suggest that unstable atmospheric stratifications, significant vertical differences in the atmospheric humidity, and beneficial large-scale atmospheric circulations play important roles in modulating the co-variability in the summer lightning and precipitation over South China. [ABSTRACT FROM AUTHOR]

Lightning matters to human life and natural fires so much that monitoring and predicting lightning are highly important. A simple proxy for climatic cloud‐to‐ground (CG) density is evaluated defined as the product of convective available potential energy (CAPE) and precipitation rate using data from 2005 to 2017 in Sichuan of Southwest China. CAPE times precipitation rate (CP) relates the monthly distribution and magnitude of negative lightning in the basin region more closely, while CP describes the monthly distribution and magnitude of positive lightning in the plateau region more appropriately. Except for individual years, the annual variation trend and magnitude of CP and positive and negative lightning are relatively consistent in the basin region, while the description of the annual variation trend and magnitude of lightning by CP in the plateau region is insufficient, especially for negative lightning. CP represents the high‐value areas of the positive and negative lightning in the basin and southern Sichuan reasonably, but misses the lightning belt in the plateau region. In general, the performance of CP for lightning in the basin is superior to that in the plateau, this may be caused by two factors, one is the particularity and complexity of lightning in the plateau resulted from special topographic and meteorological conditions, the other one is the limitation of CP caused by the fact that CP does not take into account other environmental factors contributing to lightning. The ability of this simple proxy to describe CG lightning in Sichuan is limited by vertical wind shear in the middle and lower troposphere, zero degree height, and liquid water path, mainly because the proxy does not have the ability to generalize these factors that play a key role in lightning activity. [ABSTRACT FROM AUTHOR]

Hubei Province Region (HPR), located in Central China, is a concentrated area of severe convective weather. Three severe convective processes occurred in HPR were selected, namely 14−15 May 2015 (Case 1), 6−7 July 2013 (Case 2), and 11−12 September 2014 (Case 3). In order to investigate the differences between the three cases, the temporal and spatial distribution characteristics of cloud−ground lightning (CG) flashes and precipitation, the distribution of radar parameters, and the evolution of cloud environment characteristics (including water vapor (VD), liquid water content (LWC), relative humidity (RH), and temperature) were compared and analyzed by using the data of lightning locator, S-band Doppler radar, ground-based microwave radiometer (MWR), and automatic weather stations (AWS) in this study. The results showed that 80% of the CG flashes had an inverse correlation with the spatial distribution of heavy rainfall, 28.6% of positive CG (+CG) flashes occurred at the center of precipitation (>30 mm), and the percentage was higher than that of negative CG (−CG) flashes (13%). Moreover, the quantity of thunderstorm cells in Case 1 was more than other cases, the peak time of +CG flashes was prior to that of total CG flashes in Case 2 and Case 3, and the time of +CG flashes’ peak in Case 2 was prior to that of precipitation at about 2 h. Based on the analysis of the cloud environment, there are three main reasons for the differences of CG flashes and precipitation. Firstly, the structure of the LWC vertical profile and the height of the LWC peak are different, and high LWC makes it difficult for the collision of ice particles to generate electricity. Secondly, the differences between convective available potential energy (CAPE), precipitation, and CG flashes is caused by the sudden increase of VD from 1.5 km to 3 km, and thirdly, the production of CG flashes is very sensitive to RH at the surface layer and the total CG flashes increase as the RH increasing.

Abstract: A long term (1998–2006) study of annual precipitation and cloud-to-ground (CG) lightning has been made at 31 stations over Taiwan. The CG-lightning data were collected by the ground-based Lightning Location System (LLS) built by Tai-Power Company of Taiwan while the precipitation data were collected from the Central Weather Bureau (CWB) of Taiwan. For the present study, a spatial scale of 0.1° latitude×0.1° longitude (≈102 km2) is selected to determine the flash density. CG-lightning and precipitation data are used to compute the values of “rain yield”, defined as the mass of rain produced per CG-lightning flash in units of kgfl−1 over a given surface area. The rain yield is found to vary considerably with seasonal and climatic conditions, and geographical location. A positive linear correlation is observed between precipitation and lightning flash density with a highest correlation coefficient of 0.70 over inland stations. Out of the 31 stations, 13 stations are inland stations and these stations show higher rain yields clustering close to a mean of 0.7×1010 kgfl−1, compared to the coastal stations which show a mean value 1.4×1010 kgfl−1. When the stations are classified according to seasonal climate zones, the winter and winter-dominant rainfall stations show comparatively higher value of rain yield with an average of 2.8×1010 kgfl−1 than the summer and summer-dominant rainfall stations which exhibit a significantly lower value of rain yield of 2.1×1010 kgfl−1. Inland stations exhibit a lower value of rain yield with a mean of 1.6×109 kgfl−1 and 1.4×1010 kgfl−1 respectively during warm and cold seasons compared to the coastal stations. For each station, the average cold season rain yields are significantly higher than that of warm season values. These differences in rain yield values are attributed to local surface heating which indirectly controls such parameters as cloud base height and convectively available potential energy (CAPE) in the atmosphere. The variation of rain yield with geographical, seasonal, and climatic conditions, found in our observations, are in good agreement with studies found in the literature from other parts of the world. [Copyright &y& Elsevier]

Hubei Province Region (HPR), located in Central China, is a concentrated area of severe convective weather. Three severe convective processes occurred in HPR were selected, namely 14–15 May 2015 (Case 1), 6–7 July 2013 (Case 2), and 11–12 September 2014 (Case 3). In order to investigate the differences between the three cases, the temporal and spatial distribution characteristics of cloud–ground lightning (CG) flashes and precipitation, the distribution of radar parameters, and the evolution of cloud environment characteristics (including water vapor (VD), liquid water content (LWC), relative humidity (RH), and temperature) were compared and analyzed by using the data of lightning locator, S-band Doppler radar, ground-based microwave radiometer (MWR), and automatic weather stations (AWS) in this study. The results showed that 80% of the CG flashes had an inverse correlation with the spatial distribution of heavy rainfall, 28.6% of positive CG (+CG) flashes occurred at the center of precipitation (>30 mm), and the percentage was higher than that of negative CG (−CG) flashes (13%). Moreover, the quantity of thunderstorm cells in Case 1 was more than other cases, the peak time of +CG flashes was prior to that of total CG flashes in Case 2 and Case 3, and the time of +CG flashes' peak in Case 2 was prior to that of precipitation at about 2 h. Based on the analysis of the cloud environment, there are three main reasons for the differences of CG flashes and precipitation. Firstly, the structure of the LWC vertical profile and the height of the LWC peak are different, and high LWC makes it difficult for the collision of ice particles to generate electricity. Secondly, the differences between convective available potential energy (CAPE), precipitation, and CG flashes is caused by the sudden increase of VD from 1.5 km to 3 km, and thirdly, the production of CG flashes is very sensitive to RH at the surface layer and the total CG flashes increase as the RH increasing. [ABSTRACT FROM AUTHOR]