scholarly journals Estimation of Marine Boundary Layer Heights over the Western North Pacific Using GPS Radio Occultation Profiles

SOLA ◽  
2016 ◽  
Vol 12 (0) ◽  
pp. 302-306 ◽  
Author(s):  
Fang-Ching Chien ◽  
Jing-Shan Hong ◽  
Ying-Hwa Kuo
Keyword(s):  
Boundary Layer ◽  
North Pacific ◽  
Western North Pacific ◽  
Radio Occultation ◽  
Marine Boundary Layer ◽  
Gps Radio Occultation

scholarly journals The Marine Boundary Layer Height over the Western North Pacific Based on GPS Radio Occultation, Island Soundings, and Numerical Models

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 155
Author(s):  
Fang-Ching Chien ◽  
Jing-Shan Hong ◽  
Ying-Hwa Kuo
Keyword(s):  
Boundary Layer ◽  
North Pacific ◽  
Western North Pacific ◽  
Radio Occultation ◽  
Marine Boundary Layer ◽  
Numerical Models ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Atmospheric Instability ◽  
Near Shore

This paper estimates marine boundary layer height (MBLH) over the western North Pacific (WNP) based on Global Positioning System Radio Occultation (GPS-RO) profiles from the Formosa Satellite Mission 3 (FORMOSAT-3)/Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites, island soundings, and numerical models. The seasonally-averaged MBLHs computed from nine years (2007–2015) of GPS-RO data are inter-compared with those obtained from sounding observations at 15 island stations and from the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis (ERA-Interim) and National Centers for Environmental Prediction Global Forecast System (NCEP GFS) data over the WNP from 2012 to 2015. It is found that the MBLH using nine years of GPS-RO data is smoother and more consistent with that obtained from sounding observations than is the MBLH using four years of GPS-RO data in a previous study. In winter, higher MBLHs are found around the subtropical latitudes and over oceans east of Japan, which are approximately located within the paths of the North Equatorial Current and the Kuroshio Current. The MBLH is also significantly higher in winter than in summer over the WNP. The above MBLH pattern is generally similar to those obtained from the analysis data of the ERA-Interim and NCEP GFS, but the heights are about 200 m higher. The verification with soundings suggests that the ERA-Interim has a better MBLH estimation than the NCEP GFS. Thus, the MBLH distributions obtained from both the nine-year GPS-RO and the ERA-Interim data can represent well the climatological MBLH over the WNP, but the heights should be adjusted about 30 m lower for the former and ~200 m higher for the latter. A positive correlation between the MBLH and the instability of the lower atmosphere exists over large near-shore areas of the WNP, where cold air can move over warm oceans from the land in winter, resulting in an increase in lower-atmospheric instability and providing favorable conditions for convection to yield a higher MBLH. During summer, the lower-atmospheric instability becomes smaller and the MBLH is thus lower over near-shore oceans.

scholarly journals The Role of Latent Heat Flux in Tropical Cyclogenesis over the Western North Pacific: Comparison of Developing versus Non-Developing Disturbances

2019 ◽  
Vol 7 (2) ◽  
pp. 28 ◽  
Author(s):  
Si Gao ◽  
Shengbin Jia ◽  
Yanyu Wan ◽  
Tim Li ◽  
Shunan Zhai ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
North Pacific ◽  
Western North Pacific ◽  
Specific Humidity ◽  
Near Surface ◽  
Tangential Wind

The possible role of air–sea latent heat flux (LHF) in tropical cyclone (TC) genesis over the western North Pacific (WNP) is investigated using state-of-the-art satellite and analysis datasets. The authors conducted composite analyses of several meteorological variables after identifying developing and non-developing tropical disturbances from June to October of the period 2000 to 2009. Compared to the non-developing disturbances, increased LHF underlying the developing disturbances enhances boundary–layer specific humidity. The secondary circulation then transports more boundary–layer moisture inward and upward and, thus, induces a stronger moist core in the middle troposphere. Accordingly, the air in the core region ascends following a warmer moist adiabat than that in the environment and results in a stronger upper-level warm core, which is associated with a stronger near-surface tangential wind based on the thermal wind balance. This enlarges the magnitude and negative radial gradient of LHF and, thereby, further increases boundary–layer specific humidity. A tropical depression forms when the near-surface tangential wind increases to a certain extent as a result of the continuing positive feedback between near-surface wind and LHF. The results suggest an important role of wind-driven LHF in TC genesis over the WNP.

scholarly journals Water Budget and Intensity Change of Tropical Cyclones over the Western North Pacific

2017 ◽  
Vol 145 (8) ◽  
pp. 3009-3023 ◽  
Author(s):  
Si Gao ◽  
Shunan Zhai ◽  
Baiqing Chen ◽  
Tim Li
Keyword(s):  
Boundary Layer ◽  
Tropical Cyclones ◽  
North Pacific ◽  
Water Budget ◽  
Western North Pacific ◽  
Precipitable Water ◽  
Moisture Flux ◽  
Intensity Change ◽  
Surface Evaporation ◽  
Total Precipitable Water

Three satellite observational datasets and a reanalysis dataset during the period 2001–09 are used to examine four water budget components (total precipitable water, surface evaporation, precipitation, and column-integrated moisture flux convergence) associated with western North Pacific tropical cyclones (TCs) of different intensity change categories: rapidly intensifying, slowly intensifying, neutral, and weakening. The results show that surface evaporation plays an important role in storm rapid intensification (RI) and the highest evaporation associated with rapidly intensifying TCs is associated with the highest sea surface temperature. Total precipitable water in the outer environment, where moisture is mainly provided by surface evaporation, is also vital to storm RI because RI is favored when there is less dry air intruded into the storm circulation. The roles of surface evaporation and total precipitable water in storm RI are related to the enhanced convective available potential energy by moistening and warming the boundary layer. The largest amount of column-integrated moisture flux convergence associated with weakening TCs, which results in the heaviest precipitation, is because their strongest mean intensity promotes moisture transport. It is suggested that different water budget components play different roles in TC intensity change. The results agree with the notion that TC intensity change results from a competition between surface moisture and heat fluxes and low-entropy downdrafts into the boundary layer.

scholarly journals Planetary boundary layer heights from GPS radio occultation refractivity and humidity profiles

2012 ◽  
Vol 117 (D16) ◽  
pp. n/a-n/a ◽  
Author(s):  
Chi O. Ao ◽  
Duane E. Waliser ◽  
Steven K. Chan ◽  
Jui-Lin Li ◽  
Baijun Tian ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Radio Occultation ◽  
Gps Radio Occultation ◽  
Humidity Profiles

scholarly journals Monitoring the atmospheric boundary layer by GPS radio occultation signals recorded in the open-loop mode

2006 ◽  
Vol 33 (12) ◽  
Author(s):  
S. Sokolovskiy ◽  
Y.-H. Kuo ◽  
C. Rocken ◽  
W. S. Schreiner ◽  
D. Hunt ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Radio Occultation ◽  
Open Loop ◽  
Gps Radio Occultation
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