OMI L2G and L3 Status Peter Leonard – OSST June 21, 2006

OMTO3e (0.25 o x 0.25 o ) Total Column Ozone for September 30, 2005

OMTO3e (0.25 o x 0.25 o ) Reflectivity at 331 nm for September 30, 2005

OMTO3e (0.25 o x 0.25 o ) UV Aerosol Index for September 30, 2005

Status of L2G and L3 PGEs PGE Description Status OMTO3GL2G for OMTO3In Production OMCLDRRGL2G for OMCLDRRIn Production OMNO2GL2G for OMNO2In Production OMAERUVGL2G for OMAERUVIn Production OMDOAO3GL2G for OMDOAO3In Test SIPS OMCLDO2GL2G for OMCLDO2In Test SIPS OMTO3dL3 for OMTO3 (1.25 o x 1.00 o )In Production OMTO3eL3e for OMTO3 (0.25 o x 0.25 o )Ready for Production

OMI L2G Products The “G” in L2G represents “Gridded”. Each OMI L2G product file contains 24 UTC hours of L2 data subsetted onto 0.25 o x 0.25 o longitude-latitude grid. Most L2G data and geolocation fields are three- dimensional: longitude, latitude, and candidate number. Each L2G grid cell contains as many as twelve L2 observations with centers in grid cell, ordered in time. L2G data are not averaged or weighted in any way. Can reproduce L2 swath product files from L2G files. L2G products follow “Definitions of OMI Grids for Level 3 and Level 4 Data Products” by Pepijn Veefkind et al. L2G products follows “HDF-EOS Aura File Format Guidelines” by Cheryl Craig et al.

OMI L2G Products (Continued) L2G product files are in HDF-EOS 5 grid format. L2G product files contain required HDF-EOS 5 Metadata. Geolocation and data fields are gzip internally compressed (done via HDF-EOS 5 function calls). L2G product files also contain complete suite of ECS Metadata. OMTO3G, OMCLDRRG, OMNO2G and OMAERUVG PGEs are in production. OMDOAO3G and OMCLDO2G PGEs are in Test SIPS. Is there any demand for OMBROG, OMHCHOG, OMOCLOG, OMSAO3G and/or OMSO2G products?

OMTO3d Product OMTO3d is classic TOMS-like Level 3 product (the “McPeters” Product) based on OMTO3 L2 product. The “d” in OMTO3d represents “daily”. Geographic Projection with 1.25 o x 1.00 o longitude- latitude grid. Same calendar date on ground for all L3 grid cells. Resulting map is continuous cylinder. Each OMTO3d product file is generated from three consecutive OMTO3G product files. Need final orbit (or two) from previous UTC day and first orbit (or two) from next UTC day to complete map, since each L2G file contains data from three calendar dates on ground.

08/07/05 on Ground08/06/05 on Ground08/05/05 on Ground OMTO3d (1.25 o x 1.00 o )

OMTO3d Product (Continued) OMTO3d PGE produces total ozone, reflectivity at 331 nm, and UV aerosol index product files in classic TOMS Level 3 ASCII format. OMTO3d product files are used to generate maps displayed on TOMS Web Site.

OMTO3e Product OMTO3e is high-resolution “McPeters” Product. The “e” in OMTO3e represents “expanded”. Geographic projection with 0.25 o x 0.25 o longitude- latitude grid. Each L3e grid cell is populated with L2 observation that has shortest path length [ = 1/cosine(solar zenith angle) + 1/cosine(viewing zenith angle) ]. Same calendar date on ground for all L3e grid cells. Resulting map is continuous cylinder. Each OMTO3e product file is generated from three consecutive OMTO3G product files. Need final orbits from previous UTC day and first orbits from next UTC day to complete map, since each L2G file contains data from three calendar dates on ground.

OMTO3e Product (Continued) Classic TOMS-like Level 3 tessellation scheme adopted. Total ozone, reflectivity at 331 nm, and UV aerosol index product files in classic TOMS Level 3 ASCII format. OMTO3e ASCII product files are 20 times larger in size than OMTO3d product files. OMTO3e PGE also produces single HDF-EOS 5 product file for each day containing above three fields. L3e HDF-EOS 5 product files follow “Definitions of OMI Grids for Level 3 and Level 4 Data Products” by Pepijn Veefkind et al. L3e HDF-EOS 5 product files follow “HDF-EOS Aura File Format Guidelines” by Cheryl Craig et al. L3e HDF-EOS 5 product contains required HDF-EOS 5 Metadata, but does not contain any ECS Metadata.

OMTO3e (0.25 o x 0.25 o ) Total Column Ozone for October 31, 2005

Other OMI L3 Products Jerry Ziemke (GSFC & UMBC) is creating MLS/OMI Tropospheric O 3 L3 product. Mark Wenig (GSFC & NRC) is creating OMI NO 2 L3 product. Thomas Kurosu (SAO) may be working on OMI BrO, HCHO and OClO L3 products. Nick Krotkov et al. (UMBC) may be working on OMI SO 2 L3 product. Help is available from OSST for creation of L3e or L3 products.

MLS/OMI Tropospheric Ozone L3 (0.25 o x 0.25 o ) Jerry Ziemke – GSFC & UMBC