Abstract:
Local energy generation and conversion in freezing rain and snowstorms over southern China between 26 and 28 January 2008 were investigated using the NCEP-DOE Reanalysis 2 data. In the subtropical jet, the mean kinetic energy (
Km) converts energy into interaction kinetic energy (
Ki) flow, and then transient-eddy kinetic energy (
Ke) is gained from the
Ki flow. The
Ki flow has the same orientation as the subtropical jet. The term for baroclinic conversion between
Ke and
Ae (
ωeαe) and the geopotential height advection terms were about one order of magnitude lower than the terms for the conversions between
Km and
Ki (C(
Km,
Ki)) and between
Ki and
Ke (C(
Ki,
Ke)). The transient-eddy available potential energy (
Ae) mainly obtained energy indirectly from the mean available potential energy (
Am) over central-southern China because of the interaction available potential energy (
Ai) flow. At 1200 UTC on 26 January 2008, there were two sources of
Ai flow, one over the Tibetan Plateau and the other over northeastern China. The two sources shifted eastward over time so the energy conversions also shifted eastward. The
Ai flows had two orientations, one being the orientation opposite that of the subtropical jet and the other in the same direction as the subtropical jet.