Overview of CLEX
The Cloud Layer Experiment (CLEX) is
designed to test several hypotheses and approaches developed to meet the
research objectives of three (3) of the twelve (12) research tasks under
the DoD Center for Geosciences
at CSU.
The three task areas are:
Task 10 - Measurement and Analysis of Complex Layered-Cloud Systems;
Task 5 - Detection of Cloud Liquid Water Over Land From a Combination of Microwave
and Infrared Satellite Measurements; and
Task 8 - A Multisensor Approach to the Remote Sensing of Water Vapor.
Each of these research task areas has been under study for the last 12 to 15 months and researchers in each area have considerable preliminary results. The CLEX will provide tests of the early results with the aid of a substantial new data set. Thus, results of CLEX will provide necessary input to guide research in Tasks 10, 5, and 8 during their final phases.
CLEX will capture a new cloud layer data set for cases of extensive, long-lasting non-precipitating layers of clouds. The new data will be obtained from two specially equipped aircraft and from four state-of-the-art ground-based remote sensing systems (see Appendix A). The fundamental CLEX data will consist of the time dependent morphology of layer cloud by measuring the space and time variability of:
(a) height of cloud top(s);
(b) height of cloud base(s);
(c) liquid water content;
(d) ice cloud opacity; and
(e) water cloud droplet size distribution.
In addition, CLEX will gather and analyse a wide variety of supporting meteorological data on environmental temperature, moisture, and wind profiles as well as standard surface meteorological data in and around the cloud systems. Surface radiation measurements will be made at several sites. Images of the clouds and quantitative radiance measurements will be collected from seven (7) different types of instruments carried on-board six (6) operational satellites of the DoD and NOAA.
The first phase of CLEX will cover the period of 19 June - 3 July 1996 over the Central Great Plains of CONUS. Subsequent CLEX tests will be developed as needed, especially over ocean areas. During CLEX the DoD Center of Geosciences will operate in collaboration with JPL and NASA as they concurrently test their new Airborne Cloud Radar for cloud layer profiling (see cover figure). Several other university and government groups are participating and assisting with CLEX-1. All data will be collected and organized into a central database for use by a wide group of scientists.
The following sections of this document (a) present the primary CLEX science objectives in more detail, (b) describe the CLEX observational strategy, (c) discuss the experiment operational plans, (d) provide information about CLEX instruments and expected data, and (e) provide a list of participating CLEX science groups and points-of-contact.