TY - JOUR
T1 - Effects of quasi-stationary large-scale anomalies on some mesoscale features associated with the 1993 flood
T2 - A regional model simulation
AU - Pan, Zaitao
AU - Arritt, Raymond W.
AU - Segal, Moti
AU - Chen, Tsing Chang
AU - Weng, Shu Ping
PY - 2000/12/27
Y1 - 2000/12/27
N2 - We investigate the effect of quasi-stationary large-scale anomalies on mesoscale factors contributing to the 1993 U.S. Midwest flood by performing 30-day simulations with a mesoscale model. The contributions of anomalous mesoscale features to the flood were quantified by contrasting model integrations forced by initial and lateral boundary conditions with and without large-scale anomalous stationary waves that are believed to have been responsible for the flood. Supplementing previous investigations, the present study finds the following: (1) The large-scale anomalies produced environmental conditions that favored a generation of MCC-like systems rather than individual convective cells or squall lines that would have produced less precipitation over large areas. Ambient conditions favoring mesoscale convective complex (MCC) include an intensified east-west orientation of quasi-stationary fronts, weaker upper tropospheric inertial stability, and a strong low-level jet (LLJ). (2) The anomalous ageostrophic wind component to the far south of the flood region (Texas area) and geostrophic wind component over the flood region bridged together to form an extended moisture conveyer that sustained the long-lasting 1993 flood.
AB - We investigate the effect of quasi-stationary large-scale anomalies on mesoscale factors contributing to the 1993 U.S. Midwest flood by performing 30-day simulations with a mesoscale model. The contributions of anomalous mesoscale features to the flood were quantified by contrasting model integrations forced by initial and lateral boundary conditions with and without large-scale anomalous stationary waves that are believed to have been responsible for the flood. Supplementing previous investigations, the present study finds the following: (1) The large-scale anomalies produced environmental conditions that favored a generation of MCC-like systems rather than individual convective cells or squall lines that would have produced less precipitation over large areas. Ambient conditions favoring mesoscale convective complex (MCC) include an intensified east-west orientation of quasi-stationary fronts, weaker upper tropospheric inertial stability, and a strong low-level jet (LLJ). (2) The anomalous ageostrophic wind component to the far south of the flood region (Texas area) and geostrophic wind component over the flood region bridged together to form an extended moisture conveyer that sustained the long-lasting 1993 flood.
UR - http://www.scopus.com/inward/record.url?scp=0034450322&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034450322&partnerID=8YFLogxK
U2 - 10.1029/2000JD900429
DO - 10.1029/2000JD900429
M3 - Article
AN - SCOPUS:0034450322
SN - 0148-0227
VL - 105
SP - 29551
EP - 29564
JO - Journal of Geophysical Research Atmospheres
JF - Journal of Geophysical Research Atmospheres
IS - D24
M1 - 2000JD900429
ER -