Terrain‐Enhanced Precipitation Processes Above the Melting Layer: Results From OLYMPEX

Autor: S. R. Brodzik, T. M. Schuldt, Lynn A. McMurdie, Joseph P. Zagrodnik, Angela K. Rowe, Robert A. Houze
Rok vydání: 2018
Předmět:
Atmospheric Science
010504 meteorology & atmospheric sciences
0208 environmental biotechnology
Terrain
Precipitation
orographic enhancement of precipitation
02 engineering and technology
Atmospheric sciences
01 natural sciences
Aerosol and Clouds
law.invention
Remote Sensing
Altitude
law
Earth and Planetary Sciences (miscellaneous)
Instruments and Techniques
Precipitation‐radar
Radar
Research Articles
0105 earth and related environmental sciences
Remote Sensing and Disasters
Synoptic‐scale Meteorology
Atmospheric river
020801 environmental engineering
precipitation processes
observations
Geophysics
13. Climate action
Space and Planetary Science
Middle latitudes
Atmospheric Processes
Environmental science
Hydrology
Global Precipitation Measurement
Natural Hazards
radar reflectivity
Water vapor
Research Article
midlatitude cyclones
Zdroj: Journal of Geophysical Research. Atmospheres
ISSN: 2169-8996
2169-897X
Popis: Enhancement of precipitation processes aloft over complex terrain is documented using reflectivity data from an S‐band scanning radar (NPOL) that was deployed on the west coast of Washington State during the Olympic Mountains Experiment (OLYMPEX). From November 2015 through mid‐January 2016, NPOL obtained high‐resolution data within sectors over the ocean and over the windward slopes of the Olympic Mountains. Contoured Frequency by Altitude Diagrams of radar reflectivity highlight a higher frequency of occurrence of larger reflectivities for all heights between 2 and 8 km over land compared to ocean, with the largest difference in the 4‐ to 6‐km range indicating a robust signature of enhancement aloft over the windward slopes. This enhancement pattern is found to some degree under all environmental conditions considered but is especially pronounced during periods of high vapor transport, high melting level height, southwest low‐level winds, and neutral stability. These conditions are generally associated with warm sectors of midlatitude cyclones and atmospheric rivers. Past studies have postulated that a secondary enhancement in reflectivity aloft was an intrinsic part of atmospheric river type systems. However, these results show that further significant enhancement of this signature occurs as deep moist‐neutral, high water vapor content flow is lifted when it encounters a mountain range. Reflectivity data from the dual‐precipitation radar aboard the Global Precipitation Measurement satellite also documents this reflectivity increase aloft over the Olympic Mountains compared to the adjacent ocean, showing the potential for Global Precipitation Measurement to provide reliable estimates of precipitation structure over remote mountainous regions.
Key Points Enhancement of precipitation processes is found in radar reflectivity data above the melting level over complex terrainEnhancement aloft is especially pronounced during periods of high vapor transport, onshore flow, and neutral low‐level static stabilitySatellite‐borne radar detects this enhancement so that reliable estimates of precipitation over remote mountain regions are possible
Databáze: OpenAIRE