OMI L2G and L3 Status

Peter Leonard – OSSTJune 21, 2006

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

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

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

Status of L2G and L3 PGEs

PGE Description StatusOMTO3G L2G for OMTO3 In ProductionOMCLDRRG L2G for OMCLDRR In ProductionOMNO2G L2G for OMNO2 In ProductionOMAERUVG L2G for OMAERUV In ProductionOMDOAO3G L2G for OMDOAO3 In Test SIPSOMCLDO2G L2G for OMCLDO2 In Test SIPSOMTO3d L3 for OMTO3 (1.25o x 1.00o) In ProductionOMTO3e L3e for OMTO3 (0.25o x 0.25o) 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 0.25o x 0.25o 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 1.25o x 1.00o 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 Ground 08/06/05 on Ground 08/05/05 on Ground

OMTO3d (1.25o x 1.00o)

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.

http://toms.gsfc.nasa.gov/

OMTO3e Product• OMTO3e is high-resolution “McPeters” Product.• The “e” in OMTO3e represents “expanded”.• Geographic projection with 0.25o x 0.25o 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 (0.25o x 0.25o) Total Column Ozone for October 31, 2005

Other OMI L3 Products

• Jerry Ziemke (GSFC & UMBC) is creating MLS/OMI Tropospheric O3 L3 product.

• Mark Wenig (GSFC & NRC) is creating OMI NO2 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 SO2 L3 product.

• Help is available from OSST for creation of L3e or L3 products.

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