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黄建平, Jianping
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110,-0001,():
-1年11月30日
[1] Current satellite cloud retrievals are usually based on the assumption that all clouds consist of a homogenous single layer despite the frequent occurrence of cloud overlap. As such, cloud overlap will cause large errors in the retrievals of many cloud properties. To address this problem, a multilayered cloud retrieval system (MCRS) is developed by combining satellite visible and infrared radiances and surface microwave radiometer measurements. A two-layer cloud model was used to simulate ice-over-water cloud radiative characteristics. The radiances emanating from the combined low cloud and surface are estimated using the microwave liquid water with an assumption of effective droplet size. These radiances replace the background radiances traditionally used in single-layer cloud retrievals. The MCRS is applied to data from March through October 2000 over four Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) sites. The results are compared to the available retrievals of ice water path (IWP) from radar data and show that the MCRS clearly produces a more accurate retrieval of ice-over-water cloud properties. MCRS yields values of IWP that are closest to those from the radar retrieval. For ice-over-water cloud systems, on average, the optical depth and IWP are reduced, from original overestimates, by approximately 30%. The March–October mean cloud effective temperatures from the MCRS are decreased by 10±12 K, which translates to an average height difference of~1.4 km. These results indicate that ice-cloud height derived from traditional single-layer retrieval is underestimated, and the midlevel ice cloud coverage is over classified. Effective ice crystal particle sizes are increased by only a few percent with the new method. This new physically based technique should be robust and directly applicable when data are available simultaneously from a satellite imager and the appropriate satellite or surface microwave sensor.
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黄建平, Jianping
Remote Sensing of Environment 110 (2007) 186-191,-0001,():
-1年11月30日
Observations from visible, infrared and microwave satellite instruments are integrated to detect dust storm over northwestern China. Microwave measurements are used to detect the dust storm underneath ice clouds, while visible and infrared measurements are utilized for delineating the cloud-free dust systems. Detection is based on microwave polarized brightness temperature differences (ΔTb=Tbv−Tbh) among two channels of 89 GHz and 23.8 GHz and infrared brightness temperature difference (BTD) between channels at 11 and 12 μm. It is shown that the integrated approach is better than the method solely based on infrared BTD in storm detection, especially for those dust systems covered by ice clouds. This approach is applied for the Asia dust storms cases using the data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Microwave Scanning Radiometer (AMSR-E) onboard Aqua satellite.
Multisensors,
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黄建平, Jianping
GEOPHYSICAL RESEARCH LETTERS, VOL. 33,-0001,():
-1年11月30日
[1] To provide more accurate ice cloud microphysical properties, the multi-layered cloud retrieval system (MCRS) is used to retrieve ice water path (IWP) in ice-over-water cloud systems globally over oceans using combined instrument data from Aqua. The liquid water path (LWP) of lower-layer water clouds is estimated from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) measurements. The properties of the upper-level ice clouds are then derived from Moderate Resolution Imaging Spectroradiometer (MODIS) measurements by matching simulated radiances from a two-cloud-layer radiative transfer model. The results show that the MCRS can significantly improve the accuracy and reduce the over-estimation of optical depth and IWP retrievals for ice-over-water cloud systems. The mean daytime ice cloud optical depth and IWP for overlapped ice-over-water clouds over oceans from Aqua are 7.6 and 146.4 gm2, respectively, down from the initial single-layer retrievals of 17.3 and 322.3 gm2. The mean IWP for actual single-layer clouds is 128.2 gm2.
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黄建平, HUANG
PROGRESS IN NATURAL SCIENCE Vol. 16, No. 10, October 2006,-0001,():
-1年11月30日
The
dust
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