Toward a Global Climatology of Severe Hailstorms as Estimated by Satellite Passive Microwave Imagers

Abstract

An 8-yr climatology of storms producing large hail is estimated from satellite measurements using Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E). This allows a unique, consistent comparison between regions that cannot be consistently compared using ground-based records because of varying data collection standards. Severe hailstorms are indicated most often in a broad region of northern Argentina and southern Paraguay and a smaller region in Bangladesh and eastern India. Numerous hailstorms are also estimated in the central and southeastern United States, northern Pakistan and northwestern India, central and western Africa, and southeastern Africa (and adjacent waters). Fewer hailstorms are estimated for other regions over land and scattered across subtropical oceans. Very few are estimated in the deep tropics other than in Africa. Most continental regions show seasonality with hailstorms peaking in late spring or summer. The South Asian monsoon alters the hailstorm climatology around the Indian subcontinent. About 75% of the hailstorms on the eastern side (around Bangladesh) occur from April through June, generally before monsoon onset. Activity shifts northwest to northern India in late June and July. An arc along the foothills in northern Pakistan becomes particularly active from mid-June through mid-August. The AMSR-E measurements are limited to early afternoon and late night. Tropical Rainfall Measuring Mission (TRMM) measurements are used to investigate diurnal variability in the tropics and subtropics. All of the prominent regions have hailstorm peaks in late afternoon and early evening. The United States and central Africa have the fewest overnight and early morning storms, while subtropical South America and Bangladesh have the most.

A climatology of potential severe convective environments across South Africa

“…Values over the ocean have been masked out highest density of lightning in South Africa is found to occur along the northern escarpment (east of Johannesburg) extending from the northern extent of KwaZuluNatal into the Mpumalanga Lowveld (border of South Africa and Swaziland). Similarly, estimated severe hail events are more frequent over the eastern parts of the interior of the country (Cecil and Blankenship 2012). The results here suggest a similar pattern with more potential severe environments located to the east of Johannesburg (e.g.…”

“…The spatial pattern of potential severe environments over the interior of the country is similar to that found with lightning ground flash density (Gijben 2012) and severe hail events (Cecil and Blankenship 2012). The lightning climatology produced by Gijben (2012) suggest that the Fig.…”

“…There also appears to be an eastward movement (towards the escarpment) in the location of severe days as the summer progresses. The early summer preference of potential severe storm environments over the interior of the country is also identifiable in the satellite derived severe hail global climatology developed by Cecil and Blankenship (2012). As alluded to earlier, the early summer months are dominated by high wind shear values over the interior of the country, reaching shear values of between 11 and 16 m.s −1 .…”

Forcings and feedbacks on convection in the 2010 Pakistan flood: Modeling extreme precipitation with interactive large‐scale ascent

“…They also find a strong correlation between the extreme precipitation intensity to orographic lift and column precipitable water in a 10 years reanalysis data in this region, suggesting that our findings may apply to a larger number of events. Globally, a large number of the most intense precipitation events occur in the subtropical belt during summer [Zipser et al, 2006;Cecil and Blankenship, 2012], likely results of interactions between extratropical dynamics with sufficient moisture supply from the tropics. Applying the CQG method of this study to events in other regions, e.g., Texas [e.g., Simon Wang et al, 2015] or the Middle East [e.g., de Vries et al, 2013], may be useful in identifying the most important physical factors leading to extreme precipitation events in these different regions.…”

Spatiotemporal variability of lightning activity in Europe and the relation to the North Atlantic Oscillation teleconnection pattern

“…Several papers focusing on ambient conditions favorable for the formation of thunderstorms found a strong relation between several convective parameters and thunderstorm probability, especially for severe storms (e.g., Van Delden, 2001;Brooks et al, 2003;Kunz, 2007;Mohr and Kunz, 2013). More recent studies consider data from radar or satellite as a proxy for hail (e.g., Cecil and Blankenship, 2012;Nisi et al, 2016;Puskeiler et al, 2016;Junghänel et al, 2016). These stud-ies found a strong spatial variability of hail probability that is mainly governed by the distance to the ocean and by orographic flow deviations.…”