Observing System Simulation Experiments for Hurricanes:Early results and plans for the future

Robert Atlas

NOAA Atlantic Oceanographic and Meteorological Laboratory

and

Zhaoxia Pu

Dept. of Atmospheric Sciences, University of Utah

OBSERVING SYSTEM SIMULATION EXPERIMENTS

Objectives for Hurricanes:1. Evaluate the potential impact of new (proposed) observing systems on

hurricane track and intensity predictions.

2. Evaluate tradeoffs in the design and configuration of proposed observing systems (e.g. coverage, resolution, accuracy and data redundancy).

3. Optimize sampling strategies for current and future airborne and space-based observing systems.

4. Evaluate and improve data assimilation and vortex initialization methodology for hurricane prediction.

Regional OSSEs

“Regional Natural Run”

Earlier OSSEs for Hurricanes

1. Global OSSEs Using 3&1/2 month fvGCM Nature run at .5 deg resolution - aimed at evaluating the potential impact of Doppler Lidar winds on hurricane track prediction

2. Global Quick OSSE using .25 deg fvGCM 5-day forecast as Nature - aimed at evaluating impact of wind profile observations on the forecast track for an Ivan

like hurricane and in testing hypotheses relating to hurricane track forecasting

3. Regional Quick OSSE using mm5 nature run - aimed at evaluating the potential impact of HIRAD on hurricane surface wind analyses

4. Regional Quick OSSEs using WRF ARW 3-5 day forecasts as nature runs -aimed at evaluating potential value of AIRS, Doppler Wind Lidar or other data for hurricane intensity forecasting.

Global OSSE with fvGCM NatureNATURE RUN:

FVGCM at .5 deg resolution for the period from September 11 to December 31, 1999.

GLOBAL DATA ASSIMILATION SYSTEM USED:

GEOS-3, 1 X 1 deg horizontal resolution

GEOS-4, 1 X 1.25 deg horizontal resolution

SPINUP: 35 days

PERIOD OF ASSIMILATION: Sept. 11 - Oct. 31, 1999

CALIBRATION EXPERIMENTS (REAL and SIMULATED): CTRL (Conventional Data + TOVS + CTW + QSCAT)

CTRL-ALL SAT (Conventional Data only)

CTRL-SAT TEMP (Conventional Data + CTW + QSCAT)

CTRL-QSCAT (Conventional Data + TOVS + CTW)

SIMULATED DATA EXPERIMENTS:CTRL + Lidar Winds (with varying coverage)

Potentional Impact of new

space-based observations on a

Hurricane Track Prediction

• Tracks• Green: actual track

• Red: forecast beginning 63 hours before landfall with current data

• Blue: improved forecast for same time period with simulated wind lidar

SUMMARY OF LIDAR WIND EXPERIMENTS USED IN THE HURRICANE 1 CASE STUDY

PERIOD OF ASSIMILATION: Sept. 11 - Sept. 14, 1999FIVE DAY FORECASTS: From Sept. 14, 1999

LIDAR WIND EXPERIMENTS:

CTRL + Full Lidar (complete profile and + / - 1100 km swath)CTRL + Full Lidar (no data after Sept. 13, 1999, 0.0z)CTRL + Full Lidar (no data before Sept. 13, 1999, 0.0z)CTRL + Upper Lidar (500mb and above)CTRL + Lower Lidar (1000 - 700mb)CTRL + Full non-scanning Lidar

Description of Quick OSSE Experiments

Nature Run : fvGCM .25 x .36 deg horizontal resolution, start on Sep. 11, 2004 at 12z

Observations : simulated from the Nature Run for Sep. 11, 12z – Sep.12, 12z, 2004.

Data Assimilation Experiments : fvSSI , 1 x 1.25 deg resolution, ran Sep. 11, 00z – Sep.12, 12z, 2004.

Control - compliment of operationally globally observed data, including satellite temperature profilesLidar - Idealized wind profiles added in the vicinity of the hurricane

5 Day Forecasts : Started on Sep.11, 12z, Sep.12, 00z and 12zran at both 1 x 1.25 deg and .25 x .36 deg horizontal resolution

Current and planned OSSEs for hurricanes

• OSSEs to determine potential impact of UAS and to optimize sampling strategies. (ESRL, AOML, RSMAS)

• Sensor Web OSSEs (NASA GSFC, SWA, AOML, RSMAS)

• OSSEs in support of HFIP to evaluate sampling strategies for hurricane reconnaissance, new observing systems, modeling and data assimilation and predictability. (NOAA, Academia)

Current work aimed at developing rigorous regional OSSE system for USWRP OSSE Testbed.

High Resolution Hurricane Nature Run:WRF Simulation Embedded Inside the ECMWF Nature Run

60 levels; 3km resolution; double-moment microphysics; advanced radiation schemes.

RI