ATSR-GRAPE Description

Measurements

ATSR / AATSR

Local Observation Time and Length of Data Record

10:00 AM ; 1999-2002 (ERS), 2003-2009 (Envisat)

Spatial Resolution

1 km (detection), 4 km (retrieval)

Cloud Detection

VIS/NIR/IR optimal estimation.

Retrieval Methodology

COD, CP, CRE, phase -> CT, CWP.
Cloud pressure, cloud optical depth, and effective particle radius are retrieved only during day, using an Optimal Estimation approach on the five available VIS / NIR / IR channels (0.7, 0.9, 1.6, 11, and 12 μm). Cloud water path is derived from optical depth and effective particle radius.

Ancillary input

  • ECMWF profiles (operational) and particle model.
  • References

  • Sayer, A. M., C. A. Poulsen, C. Arnold, E. Campmany, S. Dean, G. B. L. Ewen, R. G. Grainger, B. N. Lawrence, R. Siddans, G. E. Thomas, and P. D. Watts, 2011: Global retrieval of ATSR cloud parameters and evaluation (GRAPE): dataset assessment. Atmos. Chem. Phys., 11, 3913-3936.