H153-07
Land-Atmosphere Interactions in the Tropical Cyclone Maintenance or Intensification (TCMI) of TS Bill (2015)
Monday, 14 December 2020: 16:24
Virtual
Jinwoong Yoo1, Joseph A Santanello Jr2, Marshall Shepherd3, Sujay V Kumar4, Patricia Lawston Parker4,5 and Andrew M. Thomas6, (1)University of Maryland College Park, College Park, MD, United States, (2)NASA, Greenbelt, MD, United States, (3)The University of Georgia, Athens, GA, United States, (4)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (5)Earth System Science Interdisciplinary Center, COLLEGE PARK, MD, United States, (6)University of Georgia, Geography Department, Athens, GA, United States
Abstract:
Extreme weather events, such as tropical cyclones (TC) can make a big impact to society, especially when they behave unexpectedly. Most TCs weaken after landfall but in some cases the ‘Brown Ocean (BO)’ effect, describing the ability of the land surface via soil moisture to support the maintenance or intensification of tropical cyclone intensity (TCMI) after landfall, can make TC predictability a challenge. Understanding TCMI mechanisms has taken on increased notoriety in recent years, driven by
the fact that
TCs rank as one of the most-deadly extreme weather events globally. Leveraged upon a previous study that defined a TCMI modeling framework using the NASA’s Land Information System (LIS) coupled to the NASA Unified WRF (NU-WRF) system, this follow-on study explores the in-depth mechanisms of the TCMI of TS Bill (2015) over the Southern Great Plain (SGP) in the U.S. Impacts of nearly saturated soil moisture conditions and surface enthalpy flux conditions on Bill’s inland intensification were investigated by evaluating simulated track and intensity, low-level atmosphere water vapor content, and their interactions with diurnal cycle of solar radiation and synoptic mid-latitude systems.
The NU-WRF model simulations were conducted at 1-km high resolution using a 2400 by 2400 grid domain set over the vast region of the Central and mid-West U.S. capturing more than the entire life-span of the TS Bill from its development in the Gulf of Mexico through the TCMI in the SGP, and to the lysis over the Kentucky. The model simulation suggests that the high soil moisture due to precipitation in the preceding month over the Central U.S. (i.e., Great Plains) clearly played a key role in the TCMI of the Bill over the SGP, which supports the BO effect. At the same time, ample moisture advection from the Gulf of Mexico over the southeastern U.S. well incubated the TC environment over the land during the TCMI processes. The diurnal cycle of convection and nocturnal intensification of convection were also associated with the TCMI of Bill.
