Interpretation of Forecast Sensitivity Observation Impact in Data Denial Experiments

Abstract

The U.S. Navy’s global operational data assimilation and forecast system has significantly greater beneficial impact from the assimilation of global and polar Atmospheric Motion Vectors (AMVs) as compared to that from other Numerical Weather Prediction (NWP) centers. Results from an earlier multi-agency data denial inter-comparison study, presented at the 11th International Winds Working Group meeting (Baker et al. 2012a), demonstrated that this relatively large observation impact for the Navy system could be attributed to the assimilation of AMVs from multiple data providers which provided both a greater number of observations and better spatial and temporal coverage (Merkova et al. 2012). One important conclusion from Baker et al. (2012a) was that the interpretation of Forecast Sensitivity Observation Impact (FSOI; Langland and Baker 2004) for data denial studies can be problematic, particularly when the change to the Global Observing System is substantial (such as denying all satellite AMVs). Typically, such comparisons between two NWP systems for different data assimilation experiments explicitly assume that the quality of the two analyses are similar, and that the FSOI can be computed independently for the control and data denial experiments. However, this assumption may not be valid for data denial experiments with appreciable changes to the observing system. These considerations were further explored in the Baker et al. (2012b) presentation at the Fifth WMO Workshop on the impact of Various Observing Systems on Numerical Weather Prediction. These implications of data denial experiments on the interpretation of FSOI metrics are generally not well recognized. Additionally, the interpretation of FSOI may also be problematic for any set of experiments where the quality of the underlying analyses differ considerably from each other. In this chapter, the previous AMV data denial experimental studies are re-examined within the context of the implications on the interpretation of FSOI for data denial experiments.

Appendix: Definitions of Acronyms

4D-Var::

4-Dimensional VARiational data assimilation

ACARS::

Aircraft Communications, Addressing, and Reporting System

AFWA::

(U.S.) Air Force Weather Agency

AIREP::

Aircraft Report

AMDAR::

Aircraft Meteorological Data Relay.

AMSR-2::

Advanced Microwave Scanning Radiometer - 2

AMSU-A::

Advanced Microwave Sounding Unit-A

AMSU-B::

Advanced Microwave Sounding Unit-B

AMV::

Atmospheric Motion Vector

AQUA (AIRS)::

Atmospheric InfraRed Sounder, flown on the NASA Aqua satellite.

ASCAT::

Advanced Scatterometer, flown on the METOP satellites.

AVHRR::

Advanced Very High Resolution Radiometer

CIMSS/UW::

Cooperative Institute for Meteorological Satellite Studies

CLD_WIND::

AMVs from geostationary satellites (also referred to as GEO WINDS)

CrIS::

Cross-track Infrared Sounder

CrIS FSR::

Cross-track Infrared Sounder, Full Spectral Resolution

EUMETSAT::

European operational satellite agency for monitoring weather, climate and the environment from space.

FSOI::

Forecast Sensitivity to Observation Impact

GeoCSR::

Geostationary satellite Clear Sky Radiance

GMAO::

Global Modeling and Assimilation Office at NASA Goddard.

GMI::

GPM (Global Precipitation Measurement) Microwave Imager

GOES::

(U.S.) Geostationary Operational Environment Satellite

GNSS::

Global Navigation Satellite System (which includes GPS).

GPS::

Global Positioning System

GPS RO::

GPS Radio Occultation observations (also called GNSS RO).

HIRS::

High-resolution Infrared Radiation Sounder

IASI::

Infrared Atmospheric Sounding Interferometer

IR::

Infrared.

JMA::

Japanese Meteorological Agency.

LeoGeo::

CIMSS AMVs determined from composite imagery based on data from both geostationary and polar-orbiting satellites

MDCRS::

Meteorological Data Collection and Reporting System.

Meteosat::

EUMETSAT geostationary satellites, abbreviated as MET7 for Meteosat-7, MET9 for Meteosat-9, etc.

METOP::

METeorological Operational (polar-orbiting) satellites, operated by EUMETSAT.

MHS::

Microwave Humidity Sensor

MODIS::

Moderate Resolution Imaging Spectroradiometer, flown on the NASA Aqua and Terra satellites.

MTSAT::

Multi-functional Transport Satellite, geostationary satellites operated by JMA.

NASA::

(U.S.) National Aeronautics and Space Administration

NAVDAS-AR::

NRL Atmospheric Variational Data Assimilation System—Accelerated Representer.

NESDIS::

(U.S.) National Environmental Satellite and Data Information Service.

NEXRAD::

(U.S.) Next-generation Radar

NH or NHEM::

Northern Hemisphere.

NOAA::

(U.S.) National Oceanic and Atmospheric Administration

NOGAPS::

Navy Operational Global Atmospheric Prediction System

NRL::

(U.S.) Naval Research Laboratory

NWP::

Numerical Weather Prediction

OSWS::

Ocean Surface Wind Speed

OSWV::

Ocean Surface Wind Vector

PIBAL::

Pilot Balloon

SAPHIR::

Sondeur Atmosphérique du Profil d’Humidité Intertropicale par Radiométrie

SH or SHEM::

Southern Hemisphere

SHIP-BUOY::

Observations from fixed and mobile ships and buoys.

SSMIS::

Special Sensor Microwave Imager Sounder

SSMIS TPW::

Total Precipitable Water retrievals from SSMIS.

SSMIS SFC WIND::

Ocean surface wind speed retrievals from SSMIS.

SWIR::

Shortwave IR

SYNOP::

WMO-format surface data, primarily from land-based stations

TC Synth or “Synthetic”::

Synthetic observations generated from TC warning messages

TC::

Tropical Cyclone.

TEMP::

WMO-format radiosonde data (including T (temperature), wind, and q (humidity)

TMI::

TRMM (Tropical Rainfall Measuring Mission) Microwave Imager

WINDSAT-TPW::

NRL polarimetric microwave satellite Total Precipitable Water retrievals

WINDSAT SFC WIND::

WindSat wind vector retrievals

VIS::

Visible

WMO::

World Meteorological Organization

WV::

Water Vapor

WVCLD::

Cloud-Top Water Vapor

WVCLR::

Clear-Sky Water Vapor