Conditions Supporting Funnel Cloud Development in Alaska  

作　　者：Stanley G.Edwin Nicole Molders Katja Friedrich Sebastian Schmidt Richard Thoman 

机构地区：[1]Department of Atmospheric Sciences,College of Natural Science and Mathematics,University of Alaska Fairbanks,Fairbanks,AK,USA [2]Geophysical Institute,University of Alaska Fairbanks,Fairbanks,AK,USA [3]Department of Atmospheric and Oceanic Sciences,University of Colorado at Boulder,Boulder,CO,USA [4]National Weather Service Forecast Office,NOAA,Fairbanks,AK,USA

出　　处：《Atmospheric and Climate Sciences》2017年第2期223-245,共23页大气和气候科学（英文）

基　　金：the National Science Foundation(NSF),the SOARS program,the Gwichyaa Zhee Gwich’in Tribal Government,and SLOAN for financial support.

摘　　要：The characteristics and climatology of funnel clouds in Alaska were examined using operational radiosondes, surface meteorological observations, and reanalysis data. Funnel clouds occurred under weak synoptic forcing between May and September between 11 am and 6 pm Alaska Daylight Time with a maximum occurrence in July. They occurred under Convective Available Potential Energy >500 J·kg-1 and strong low-level wind shear. Characteristic atmospheric profiles during funnel cloud events served to develop a retrieval algorithm based on similarity testing. Out of more than 129,000 soundings between 1971 and 2014, 2724, 442, and 744 profiles were similar to the profiles of observed funnel cloud events in the Interior, Alaska West Coast, and Anchorage regions. While the number of reported funnel clouds has increased since 2000, the frequency of synoptic situations favorable for such events has decreased.The characteristics and climatology of funnel clouds in Alaska were examined using operational radiosondes, surface meteorological observations, and reanalysis data. Funnel clouds occurred under weak synoptic forcing between May and September between 11 am and 6 pm Alaska Daylight Time with a maximum occurrence in July. They occurred under Convective Available Potential Energy >500 J·kg-1 and strong low-level wind shear. Characteristic atmospheric profiles during funnel cloud events served to develop a retrieval algorithm based on similarity testing. Out of more than 129,000 soundings between 1971 and 2014, 2724, 442, and 744 profiles were similar to the profiles of observed funnel cloud events in the Interior, Alaska West Coast, and Anchorage regions. While the number of reported funnel clouds has increased since 2000, the frequency of synoptic situations favorable for such events has decreased.

关 键 词：Alaska Funnel Clouds Funnel Cloud Climatology Similarity Retrieval Algorithm Mesoscale Forcing for Funnel Cloud Formation in Alaska 

分 类 号：P4[天文地球—大气科学及气象学]