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Dbz space drop rate6/2/2023 ![]() ![]() In this paper, we present an analysis of severe convective windstorms, i.e., squalls and tornadoes reported between 19 in the Perm region (northeast of European Russia), where a local maximum in the frequency of such events was previously found. An analysis of the climatology and formation environments of these events is essential for risk assessments, forecast improvements and identifying of links with the observed climate change. Severe convective windstorms and tornadoes regularly hit the territory of Russia causing substantial damage and fatalities. We hope this study can benefit OT monitoring in operational weather forecasting. This study provides a scientific basis for determining the geographical characteristics of OT frequency and explores the application of this OT objective detection algorithm in the operational forecast of strong convective weather. Additionally, this dataset also reveals the close connection between the seasonal shift of OT and the seasonal average precipitation distribution around the globe. There are obvious differences between OT events on land and sea. It is found that OT events are mainly concentrated in equatorial and low latitude regions, with higher frequency in summer. Then, the OT is statistically analyzed in a long time series. The accuracy of the new algorithm in identifying OT is verified by manually comparing it with the radar echo images and the cloud images of MODIS 250 m. In this study, we develop a new objective OT detection algorithm based on geostationary satellite observations from 2006 to 2017. Therefore, the timely detection of OT can help improve the accuracy of forecasting. OT is closely related to severe weather and can influence water vapor transport and the material exchange between the troposphere and stratosphere. Overshooting cloud top (OT) is the product of strong updrafts in convective storms, which can penetrate the tropopause and enter the lower stratosphere. Thus, it is necessary to improve the forecast accuracy of strong convective storms. ![]() It often occurs suddenly and can cause huge disasters. This study provides OT climatology for the first time, as derived from 2 decades of MODIS data, that represents the longest and stable satellite records.Ī strong convective storm is a disastrous weather system with a small spatio-temporal scale. The top 10 coldest OTs from both Terra and Aqua mostly occur over land and at night. OTs over land are usually colder than over ocean, except at around 10:30 LT (Equator-crossing time). Maximum OT occurrences are in the afternoon over most land areas and around midnight over ocean, and the OT diurnal cycle is stronger and more varied over land than over ocean. OT diurnal variations agree with the known diurnal cycle of convection. Seasonal OT variations shift with large-scale climate systems such as the ITCZ and local monsoonal systems, including the South Asian monsoon, North American monsoon, and West African monsoon. OT spatial distributions show strong seasonal and diurnal variabilities. OTs appear most frequently over the Intertropical Convergence Zone (ITCZ), central and southeastern North America, tropical and subtropical South America, southeastern and southern Asia, tropical and subtropical Africa, and northern middle–high latitudes. ![]() The OT climatology reveals a pattern that follows the climatology of deep convection and shallow convection over the midlatitude oceans during winter cold-air outbreaks. We demonstrate that the overall accuracy of our approach is about 0.9 when the probability of the OT candidates is larger than 0.9. The algorithm is based on a logistic model which is trained using A-Train observations. Here, we develop an OT detection algorithm using thermal infrared (IR) channels and apply this algorithm to about 20 years' worth of MODIS data from both Terra and Aqua satellites to form an extensive, near-global climatology of OT occurrences. An OT is a well-known indicator of convective updrafts and severe weather conditions. Overshooting cloud tops (OTs) form in deep convective storms when strong updrafts overshoot the tropopause.
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