ASDC | TL2CH4N

TES Level 2

Entry Title: TES/Aura L2 Methane Nadir V007

Entry ID: TL2CH4N_7

Clouds

Description

TL2CH4N_7 is the Tropospheric Emission Spectrometer (TES)/Aura Level 2 Methane Nadir Version 7 data product. TES was an instrument aboard NASA's Aura satellite and was launched from California on July 15, 2004. Data collection for TES is complete. TES Level 2 data contain retrieved species (or temperature) profiles at the observation targets and the estimated errors. The geolocation, quality, and other data (e.g., surface characteristics for nadir observations) were also provided. L2 modeled spectra were evaluated using radiative transfer modeling algorithms. The process, referred to as retrieval, compared observed spectra to the modeled spectra and iteratively updated the atmospheric parameters. L2 standard product files included information for one molecular species (or temperature) for an entire global survey or special observation run. A global survey consisted of a maximum of 16 consecutive orbits.

Nadir observations, which point directly to the surface of the Earth, are different from limb observations, which are pointed at various off-nadir angles into the atmosphere. Nadir and limb observations were added to separate L2 files, and a single ancillary file was composed of data that are common to both nadir and limb files. A Nadir sequence within the TES Global Survey was a fixed number of observations within an orbit for a Global Survey. Prior to April 24, 2005, it consisted of two low resolution scans over the same ground locations. After April 24, 2005, Global Survey data consisted of three low resolution scans. The Nadir standard product consists of four files, where each file is composed of the Global Survey Nadir observations from one of four focal planes for a single orbit, i.e. 72 orbit sequences. The Global Survey Nadir observations only used a single set of filter mix.

A Global Survey consisted of observations along 16 consecutive orbits at the start of a two day cycle, over which 3,200 retrievals were performed. Each observation was the input for retrievals of species Volume Mixing Ratios (VMRs), temperature profiles, surface temperature, and other data parameters with associated pressure levels, precision, total error, vertical resolution, total column density, and other diagnostic quantities. Each TES Level 2 standard product reported information in a swath format conforming to the HDF-EOS Aura File Format Guidelines. Each Swath object was bounded by the number of observations in a global survey and a predefined set of pressure levels representing slices through the atmosphere. Each standard product could have had a variable number of observations depending upon the Global Survey configuration and whether averaging was employed. Also, missing or bad retrievals were not reported. Further, observations were occasionally scheduled on non-global survey days. In general they were measurements made for validation purposes or with highly focused science objectives. Those non-global survey measurements were referred to as “special observations”

The organization of data within the Swath object was based on a superset of the Upper Atmosphere Research Satellite (UARS) pressure levels used to report concentrations of trace atmospheric gases. The reporting grid was the same pressure grid used for modeling. There were 67 reporting levels from 1211.53 hPa, which allowed for very high surface pressure conditions, to 0.1 hPa, about 65 km. In addition, the products reported values directly at the surface when possible or at the observed cloud top level. Thus in the Standard Product files, each observation could potentially contain estimates for the concentration of a particular molecule at 67 different pressure levels within the atmosphere. However, for most retrieved profiles, the highest pressure levels were not observed due to a surface at lower pressure or cloud obscuration. For pressure levels corresponding to altitudes below the cloud top or surface, where measurements were not possible, a fill value was applied.

To minimize the duplication of information between the individual species standard products, data fields common to each species (such as spacecraft coordinates, emissivity, and other data fields) was collected into a separate standard product, termed the TES L2 Ancillary Data product (Short name: TL2ANC). Users of this product should also obtain the Ancillary Data product.

DOI

10.5067/AURA/TES/TL2CH4N_L2.007

Citation Styles for this Dataset

VIEW RELATED INFORMATION

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)

NASA EOS ATB Documents: TES

DATA CITATION POLICY

How to cite ASDC data

DATA QUALITY

GENERAL DOCUMENTATION

Overview of TES Data at the ASDC - 2015

PI DOCUMENTATION

PROCESSING HISTORY

TES Data Processing Calendar
TES Level 2 Versioning - Level 2 Standard and Special Observation Products

PRODUCT USAGE

TES Langley ASDC Project Guide

PRODUCTION HISTORY

PUBLICATIONS

Earth Observing System Data and Information System (EOSDIS) Article: On the trail of global pollution drift

TES Publications

READ-ME

Basic IDL Tools for extraction information from TES L2 HDF Product files

SCIENCE DATA PRODUCT VALIDATION

Earth Observing System (EOS) Tropospheric Emission Spectrometer (TES) Data Validation Report (Version F08_11 data) - Version 7.0

USER FEEDBACK PAGE

HDF Support Portal

USER'S GUIDE

From GCMD Science Keywords:

METHANE > CARBON AND HYDROCARBON COMPOUNDS
AIR QUALITY
ATMOSPHERIC OZONE > OXYGEN COMPOUNDS
CLOUDS
CLOUD PROPERTIES
CLOUD MICROPHYSICS
ATMOSPHERIC TEMPERATURE
NON-METHANE HYDROCARBONS/VOLATILE ORGANIC COMPOUNDS > CARBON AND HYDROCARBON COMPOUNDS
VOLATILE ORGANIC COMPOUNDS
ATMOSPHERIC CHEMISTRY
CLOUD OPTICAL DEPTH/THICKNESS > CLOUD MICROPHYSICS
SURFACE TEMPERATURE
CARBON AND HYDROCARBON COMPOUNDS
CLOUD TOP PRESSURE > CLOUD PROPERTIES
OXYGEN COMPOUNDS

Resolution: 0.5 Km Along Track
Resolution: 5 Km Cross Track

Data Distribution

File Format(s):

HDF-EOS5

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Spatial Information

Spatial Coverage: (S: -90, N: 90), (W: -180, E: 180)
Spatial Coverage Type: Horizontal
Coordinate System: Cartesian
Granule Spatial Representation: Cartesian

Locations

GLOBAL

Temporal Information

Temporal Coverage: 2004-08-22 - 2018-01-22

Platforms

Earth Observation Satellites

Aura

Earth Observing System, Aura

TES

Tropospheric Emission Spectrometer

FTIR SPECTROMETER

Metadata Dates

Created on 2019-07-09

Last updated on 2020-11-24