摘要: The DOE's Atmospheric Radiation Measurement (ARM) Program employs both upward-211and downward-looking remote-sensing instruments to measure the horizontal and 211vertical distributions of clouds across its Southern Great Plains ... 展开 The DOE's Atmospheric Radiation Measurement (ARM) Program employs both upward-211and downward-looking remote-sensing instruments to measure the horizontal and 211vertical distributions of clouds across its Southern Great Plains (SGP) site. No 211single instrument is capable of completely determining these distributions over 211the scales of interest to ARM's Single Column Modeling (SCM) and Instantaneous 211Radiative Flux (IRF) groups; these groups embody the primary strategies through 211which ARM expects to achieve its objectives of developing and testing cloud 211formation (USDOE, 1996). Collectively, however, the data from ARM's cloud-211detecting instruments offer the potential for such a three-dimensional 211characterization. Data intercomparisons, like the ones illustrated here, are 211steps in this direction. Specifically, they are valuable because they help: 211provide a measure of uncertainty in ARM's measurement capabilities, calibrate 211retrieval methods and refine algorithms and concepts. In the process, we are 211forced to think of meaningful ways in which measurements from different 211instruments can be compared and, perhaps, combined. While the ultimate goal of 211this particular effort is to develop the ability to accurately characterize cloud 211fields in three dimensions over time at the SGP site, along the way we will 211address such questions as which source, or combination of cloud data sources, 211offers a best estimate product and how can cloud observations be used to evaluate 211the representation of clouds in numerical models. Examples of some initial 211comparisons, involving satellite, millimeter cloud radar, whole sky imager and 211ceilometer data, are provided herein. 收起