Building a Weather-Ready Nation // 1NATIONAL WEATHER SERVICE

NATIONAL WEATHER SERVICE

Evaluation of the impact of various observing systems on forecast skill in the NCEP Global Forecast System (GFS)November 30, 20207th WMO Workshop on the Impact of Various Observing Systems on NWP

Catherine Thomas1, Daryl Kleist1, Iliana Genkova2, Hui Shao3, Kristen Bathmann2, Haixia Liu2, Xingren Wu2, Vijay Tallapragada1, Peter Black2, Stephen Lord1, Fanglin Yang1

1 NOAA/NWS/NCEP/EMC, 2 IMSG @ NOAA/NWS/NCEP/EMC, 3 JCSDA

Building a Weather-Ready Nation // 2NATIONAL WEATHER SERVICE

Recent and Planned Upgrades to the GFS• GFSv15.1 (June 2019)

• Initial implementation of FV3-based GFS

• Increase analysis increment & ensemble resolution

• GFSv15.2 (November 2019)• GOES-17 AMVs, KOMPSAT-5

GPS, METOP-C AMSU-A and MHS

• NSST Updates

• GFSv15.3 (May 2020)• COSMIC-2

• GFSv16 (February 2021)• 127 Layers, ~80km model top • Modulated-ensemble LETKF• 4D-IAU• Correlated observation errors• VarQC re-design• Metop-C GNSSRO• Geostationary CSR• HDOB

• GFSv16.1 (TBD)• Leo-Geo AMVs• GMI, Precipitation affected MW• NPP OMPS-LP, N20 OMPS-NP/TC

Building a Weather-Ready Nation // 3NATIONAL WEATHER SERVICE

Forecast Impacts of COSMIC-2Hui Shao, Kristen Bathmann

COSMIC-2 has a constellation of six satellites, providing about 5000 occultations per day concentrated between 45S-45N latitude. It was launched on June 25, 2019, and its data have been officially released to the public since March 6, 2020.

COSMIC-2

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Forecast Impacts of COSMIC-2Hui Shao, Kristen Bathmann

Bias RMSE

Blue indicates COSMIC-2 reduced forecast errorsRed indicates COSMIC-2 degraded forecast errors

The COSMIC-2 data are showing qualitative positive (blue) impacts on forecasts for most fields.

The results are verified against in-situ observations

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Forecast Impacts of COSMIC-2Hui Shao, Kristen Bathmann

Comparison of forecast temperature error with and without assimilating COSMIC-2 data in the Tropics.

In situ data have been used to verify the results.

Building a Weather-Ready Nation // 6NATIONAL WEATHER SERVICE

Geostationary RadiancesHaixia Liu

SEVIRI_M11 SEVIRI_M08 AHI_HIM8 ABI_G16

Meteosat-11 Clear Sky Radiance (CSR) are currently operational in GFSv15

GFSv16 will include CSR from

• Meteosat-8 SEVIRI• Himawari-8 AHI• GOES-16 ABI

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Geostationary RadiancesHaixia Liu

RMS of RH Analysis Increments Data Counts from MHS Metop-A

Control: M11 SEVIRI onlyExperiment: With additional CSRs

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Impact of Aircraft High Density Observations (HDOBs)on GFS.v16 Tropical Cyclone Forecast

Xingren Wu, Fanglin Yang, Vijay Tallapragada, Daryl Kleist

• High-density/high-accuracy observations (30 second average) from tropical cyclone reconnaissance aircraft.

• Changes to the GFS are motivated by the successes in HWRF data assimilation.

• Cycled full resolution experiment covering:

• 2018090206-2018091900; 2019082200-2019100206; 2020060100-2020061218; 2020072100-2020080600

• Adding HDOBs in GFSv16 will improve hurricane track (left panel) and intensity (right panel) forecasts in the Atlantic and the Western Pacific, and neutral impact on track forecasts with slight degradation for intensity forecasts in the East Pacific (not shown).

Building a Weather-Ready Nation // 9NATIONAL WEATHER SERVICE

Dropsonde Data Impact Study of SHOUT/EPOCH Global Hawk in the NCEP Operational GFS

Xingren Wu, Vijay Tallapragada, Peter Black• Cycled control (GHON) and data denial experiments conducted

using NCEP operational GFSv15 with fully cycled 4D-Hybrid En-Var Data Assimilation System.

• NOAA/SHOUT 2016: 2016082100-2016091000; 2016092206-2016101900

• NASA/EPOCH 2017: 2017080700 – 2017100100

• Direct positive impacts during the cycles of the actual Global Hawk flight times

• 10-15% improvement in North Atlantic basin tropical cyclone track forecast errors, especially for days 2-4.

• Some improvements in the intensity forecast skill (especially at day-1 and day-3).

• Indirect positive impacts over the experiments periods (not shown).

Building a Weather-Ready Nation // 10NATIONAL WEATHER SERVICE

Atmospheric River Reconnaissance Dropsonde Data Impact in the NCEP Operational GFS

Xingren Wu, Vijay Tallapragada, Stephen J. Lord

• Total 32 IOPs, 46 AF C-130 and 16 G-IV missions, 1384 drops assimilated operationally in real-time (2016-2020).

• Data denial experiments conducted using NCEP operational GFSv15 with fully cycled 4D-Hybrid En-Var Data Assimilation System for the entire duration of AR Recon missions.

• Significant (10-30%) improvements are noted in the medium range synoptic forecasts over the Pacific North American region, and precipitation over the West Coast.

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LEO-GEO Atmospheric Motion VectorsIliana Genkova

• High-latitude winds from combined geostationary and polar-orbiting satellite imagery• Fills a data-gap in AMVs coverage• Add to observation sparse region near

polar jet stream

OmF (m/s), Sept - Oct 2018

ECMWF Monitoring Page

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LEO-GEO Atmospheric Motion VectorsIliana Genkova

Fit to Radiosondes

500 hPA ACC

Vector Wind RMSE

LEO-GEO AMVs has a positive impact on the winds in the Southern Hemisphere.

Impact is neutral in most other locations and variables. NH

SH

NH SH

Forecast Hour Forecast Hour

Building a Weather-Ready Nation // 13NATIONAL WEATHER SERVICE

Looking Ahead- Observations explored for future GFS implementations (GFSv16.1+)

- GOES-17 ABI CSR- NPP OMPS-LP- NOAA-20 OMPS-NP, TC- Commercial GNSSRO- GMI- Precipitation-affect MW radiances- Stereo AMVs (GOES/GOES, GOES/Himawari)- VIIRS for near sea surface temperature (NSST) analysis

- Joint Effort for Data assimilation Integration (JEDI) and the Unified Forward Operator (UFO): GFSv17+ (~2023)