Latest Documents

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    D3R Technical Specifications
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    Detailed specifications document for the Dual-Frequency, Dual-Polar, Doppler Radar (D3R)

  • Scientific and Engineering Overview of the NASA Dual-Frequency Dual Polarized Doppler Radar (D3R) System for GPM Ground Validation
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    ABSTRACT:

    As an integral part of Global Precipitation Measurement (GPM) mission, Ground Validation (GV) program proposes to establish an independent global cross-validation process to characterize errors and quantify uncertainties in the precipitation measurements of the GPM program. A ground- based Dual-Frequency Dual-Polarized Doppler Radar (D3R) that will provide measurements at the two broadly separated frequencies (Ku- and Ka-band) is currently being developed to enable GPM ground validation, enhance understanding of the microphysical interpretation of precipitation and facilitate improvement of retrieval algorithms. The first generation D3R design will comprise of two separate co- aligned single-frequency antenna units mounted on a common pedestal with dual-frequency dual-polarized solid- state transmitter. This paper describes the salient features of this radar, the system concept and its engineering design challenges.

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    Realization of the NASA Dual-Frequency Dual-Polarized Doppler Radar (D3R)
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    ABSTRACT:

    This paper describes some of the novel technologies adopted in the realization of the NASA Dual-frequency Dual- polarized Doppler Radar (D3R) system for to be used by the GPM ground validation program. A description of the transceivers and major trades that lead to a solid-state architecture is presented. Other aspects enabling the design such as the waveform design and generation and the digital receiver is also described. Data measured from a similar power amplifier was used to estimate the expected range side lobe performance. An estimate of the expected sensitivity based on the transceiver parameters also presented.

  • GPM Ground Validation Science Implementation Plan
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    The Global Precipitation Measurement mission (GPM) Ground Validation (GV) Science Implementation Plan (GVSIP) applies three overarching approaches to validation of GPM satellite constellation measurements, products, and algorithms. These approaches include:

    • National Networks: Contributions of calibrated ground observations from operational and research instruments, regional and continental scale precipitation and hydrological products with associated error models, the development of downscaling models, and other related activities on large regional or continental scales;
    • Physical Process studies and field campaigns: Contributions of targeted ground and aircraft measurements of cloud microphysical properties, precipitation, radar reflectivity, and radiances; modeling activities related to atmospheric simulation and retrieval algorithm testing; other relevant observations on local to regional scales
    • Integrated hydrometeorology applications: Contributions related to assessment of satellite precipitation products at integrated hydrological sites using stream gauges and other hydrological measurements, formulation and application of downscaling methodologies, and analysis of the utility of satellite precipitation products for basin-scale water budget studies.
  • Validation Network Data Product User’s Guide - Volume 1 (TRMM)
    Publication Date:
    07/15/2014
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    This document provides a basic set of documentation for the data products available from the GPM Ground Validation System (GVS) Validation Network (VN). In the GPM era the VN performs a direct match-up of GPM’s space-based Dual-frequency Precipitation Radar (DPR) data with ground radar data from the U.S. network of NOAA Weather Surveillance Radar-1988 Doppler (WSR-88D, or “NEXRAD”). Ground radar networks from international partners are also part of the VN. The VN match-up will help evaluate the radar reflectivity attenuation correction algorithms of the DPR and will identify biases between ground observations and satellite retrievals as they occur in different meteorological regimes. A prototype of the required capability was developed using a match-up of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data with ground-based radar (GR) measurements from a set of WSR-88D sites along the southeastern coast of the U.S.  TRMM data and their matching GR observations continue to be part of the VN operations in the GPM era. Volume 1 of the Validation Network Data User’s Guide describes the legacy TRMM-specific VN data set.  Refer to Volume 2 of the Validation Network Data User’s Guide for a description of the GPM core and constellation VN data set.

     

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    MC3E Science Plan
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    Science plan for the Mid-Continent Convective Clouds Experiment (MC3E), scheduled for the spring of 2011. This campaign will be conducted in cooperation with the Department of Energy's (DoE) Atmospheric Radiation Program (ARM). The field campaign will be conducted in south-central Oklahoma. The goal of the campaign is to contribute to the improvement of radar and microwave precipitation retrieval algorithms over land.

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    TRMM Senior Review Proposal 2007
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    Publication Date:
    03/15/2007
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    Excerpt:

    "Enclosed is the 2007 TRMM Senior Review proposal in response to NASA's request. We are very excited about the continuation of the TRMM mission.

    The first-time use of both active and passive microwave instruments and the precessing, low inclination orbit (35 degrees) have made TRMM the world's foremost satellite for the study of precipitation and associated storms and climate processes in the tropics. TRMM has met and exceeded its original goal of advancing our understanding of the distribution of tropical rainfall and its relation to the global water/energy cycles and weather..."

  • 2005 GPM Program Status Overview
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    The opening presentation given at the 2005 GPM System Definition Review meeting.

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    At the Core: Global Precipitation Measurement Mission
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    Publication Date:
    11/01/2010
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    "Next-generation unified precipitation observations from space will refine global data using the latest satellite technology"

    An article from the publication Meteorological Technology International. It provides an overview of the GPM mission and it's goals, as well as a description of the Helsinki ground validation field experiment.

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