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GPS Radio Occultation Boundary Layer Depth Seasonal L3 V1 (GPSROZPBLS) at GES DISC

Metadata Updated: December 7, 2023

This dataset provides seasonal averages of a global planetary boundary layer (PBL) height climatology derived from the COSMIC/FORMOSAT-3 and TerraSAR-X Global Positioning System (GPS) radio occultation (RO) measurements from June 2006 to December 2015.

The COSMIC/FORMOSAT-3 mission consists of a six-satellite constellation launched in 2006. Each satellite carries the IGOR GPS receiver and is equipped with fore and aft looking antenna to track both setting and rising occultations. The constellation provides globally distributed measurements across different local times. The TerraSAR-X (TSX) is a X-band SAR imaging satellite with GPS RO being a secondary measurement. It also carries an IGOR receiver and has been collecting GPS RO measurements since 2011. The instrument tracks the L-band microwave signal broadcast by a GPS satellite in a limb-viewing geometry. The IGOR receivers on COSMIC and TSX are capable of tracking the GPS signals in open loop through the middle to lower troposphere, which is essential for obtaining data with high quality for PBL height estimation, especially at low latitudes. The refractivity profiles from COSMIC and TSX form the basis for this PBL height product.

For each occultation, the PBL height is calculated as the height where the vertical gradient of the refractivity (dN/dz) is minimum. This algorithm is designed to locate the height where a large vertical change in refractivity occurs, corresponding to the transition from the free troposphere to the PBL. More details can be found in Ao et al. (2012). Each PBL height is associated with a time (starting time of the occultation) and location (latitude and longitude of the tangent point at the minimum altitude). The PBL height data are then binned into 2 degree x 2 degree latitude/longitude regions and averaged to produce the mean and standard deviation values in the climatology products. The refractivity profile has a vertical resolution of about 200 m and represents an along path horizontal averaging of ~100 km. Thus, occultations with tangent points near the coast may represent averaging over both land and ocean and should be interpreted with care.

The refractivity gradient method used here is not the only method that can be used to estimate the PBL height. Other algorithms have been proposed, including looking at "breakpoint" instead of minimum gradient, wavelet covariance transform, and using variables like bending angles or specific humidity instead of refractivity. However, the basic principle is the same. The difference between the different algorithms is small where the PBL is well-defined, with a strong capping inversion.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date November 12, 2020
Metadata Updated Date December 7, 2023

Metadata Source

Harvested from NASA Data.json

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Additional Metadata

Resource Type Dataset
Metadata Created Date November 12, 2020
Metadata Updated Date December 7, 2023
Identifier C1562324239-GES_DISC
Data First Published 2018-07-02
Language en-US
Data Last Modified 2018-07-02
Category MEaSUREs, geospatial
Public Access Level public
Bureau Code 026:00
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Citation Chi Ao, Peter Kalmus, Matthew Lebsock, Joao Teixeira. 2018-08-15. GPSROZPBLS. Version 1. GPS Radio Occultation Boundary Layer Depth Seasonal L3 V1. Greenbelt, MD, USA. Archived by National Aeronautics and Space Administration, U.S. Government, Goddard Earth Sciences Data and Information Services Center (GES DISC).
Creator Chi Ao, Peter Kalmus, Matthew Lebsock, Joao Teixeira
Graphic Preview File
Harvest Object Id 0a6c6594-b2dd-43ff-bf7b-c2b65bca1c7f
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL
Metadata Type geospatial
Old Spatial -180.0 -90.0 180.0 90.0
Program Code 026:001
Release Place Greenbelt, MD, USA
Source Datajson Identifier True
Source Hash 60b10f9c92826648216df6e12a58f6b43f5d4340d5a21be452ffc0f959ffafc5
Source Schema Version 1.1
Temporal 2006-06-01T00:00:00Z/2015-12-31T23:59:59Z

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