Assessing the minimum requirements of Doppler wind lidar measurements for seasonal climate studies a

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Assessing the minimum requirements of Doppler
wind lidar measurements for seasonal climate
studies and high impact weather forecasting
Recent progress and future plan
Zhaoxia Pu University of Utah, Salt Lake City,
UT Bruce Gentry NASA/GSFC, Greenbelt, MD Belay
Demoz Howard University, Washington, DC
Acknowledgements Dr. Ramesh Kakar, NASA/HQ
Dr. Michiko
Masutani, EMC/NCEP
Meeting of the Working Group on Space-Based Lidar
Winds Wintergreen, VA, July 8 11, 2008
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• Outline
• Background
• Objective
• Research components
• Recent progress and preliminary results
• Future work

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• Background
• NASA has classified tropospheric wind profiling
  as high-priority science and invested in wind
  profiling instrument development efforts.
• It is anticipated the future Doppler wind lidar
  (DWL) measurements could be helpful for both
  seasonal climate studies and high-impact weather
  forecasting
• Objective
• Under a NASA supported research project, our
  main research goal is to assess the minimum
  requirements of DWL measurements to fulfill the
  needs for 1) seasonal climate studies, and 2)
  analysis and forecasting of mesoscale high-impact
  weather Systems, such as hurricanes and winter
  storms etc.

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Research components

• I. Determine the minimum requirements (areas
  that must be targeted resolution, accuracy etc.)
  of DWL measurements in representing the
  seasonal variability of global wind profiles.
• Investigate the climatology of global wind
  profiles and
• uncertainties of current global wind analysis
• Analyze the error characteristics of the future
  DWL measurements
• from recent available data (e.g., GLOW,
  coherent wind lidar data etc.)
• Compare the climatology of global wind profiles
  with the
• statistics of expected Doppler lidar
  wind profiles
• II. Determine the minimum configuration
  (resolution, components, error tolerance) of DWL
  measurements in improving high impact weather
  forecasting
• Mesoscale Observing System Simulation Experiments
  (OSSEs)

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The uncertainties of global wind analysis
NCEP/NCAR Reanalysis vs. ERA-40, 1980-1999
Mean wind speed and vector differences between
two reanalyses at 850mb
Mean wind speed and vector from NCEP reanalysis
at 850mb
Mean wind speed and vector differences between
two reanalyses at 500mb
Mean wind speed and vector from NCEP reanalysis
at 500mb
The analyses tends to be different when
observations are lack in some areas. This implies
the wind observations must be sampled in these
areas where the analysis is mostly uncertain.
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Uncertainties in global wind analysis
NCEP/NCAR Reanalysis vs. ERA-40, (1980-1999 )
Seasonal variability of meridianally averaged v,
DJF(winter) vs. JJA(summer)

• There is difference in terms of
• the seasonal wind variability
• represented by two reanalysis
• products (at least in the
• magnitude of the variability)
• It is important that the future DWL
• data could be helpful to accurately
• present the seasonal wind variability.

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Variation of monthly mean wind speed with
height over the East Coast areas of US (65W-85W,
25N-50N) from ECMWF reanalysis (1980-1999)
Future Doppler Lidar Wind should be good enough
to detect monthly and seasonal variations of the
wind profiles in details
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IHOP_2002 Domain and Instrumentation

• Lidars (7)
• SRL, GLOW, HARLIE, DLR, LASE, LEANDRE-II, HRDL
• Aircraft (6)
• NASA DC-8, NRL-P3, DLR-FALCON, LEAR Jet, UW King
  Air, Proteus
• Mobile Radars(5)
• W-band (UMASS, OU), SMART-R, (2) DOWs (Penn
  State), XPOW (U Conn)
• Mobile Mesonet
• Oklahoma Mesonet
• ARM SGP facilities
• GOES satellite
• GPS, AERONET, etc

Homestead
Spol

• GSFC/LIDAR Highlights
• First simultaneous deployment for SRL, GLOW,
  HARLIE
• First attempt at extended lidar operation

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Error characteristics of the data from Goddard
Lidar Observatory for Winds (GLOW)
Mean and Standard Derivation from data collected
during IHOP (for May 2002)
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Altitude distribution
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Wind speed distribution
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Wind direction distribution
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Sonde speed vs Lidar speed50 m, 3 minute
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Speed difference distribution(Lidar-sonde)
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June 21, 2002, low level jet at Homestead, OK
Sonde
GLOW
Wind features agree well below the 4km GLOW data
show more detailed structures
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Work in progress

• Continue on investigating the climatology of
  global wind profiles
• and uncertainties in current global wind analysis
• Analyze the error characteristics of the wind
  lidar data from
• GLOW
• Expected near future progress
• Obtain the expected Doppler Lidar wind profiles
  from
• the GLOW wind data, coherent wind lidar data, as
  well as profiler
• and sondes data from the Howard Beltsville site
  when they are
• available
• Compare the climatology of global wind profiles
  with the
• statistics of expected Doppler lidar wind
  profiles

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Mesoscale OSSEs

• General Concept of OSSE (courtesy of R. Atlas
  2008)

• For mesoscale OSSEs
• Nature -- ECMWF nature run (T799NR)
• Data assimilation system -- Weather
  Research and Forecasting (WRF)
• model and its four-dimensional variational
  data assimilation (4DVAR) system
• Simulated observations Doppler Lidar Winds

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• Current activity -- work in progress
• Involve in a joint OSSEs (Masutani 2008)
• Evaluate hurricane cases in the ECMWF natural
  runs at both T799 and
• T511 resolutions
• Evaluate winter storm cases from ECMWF natural
  run (T511 NR)

• Future work
• Identify the hurricane and winter storm cases
  from ECMWF natural runs
• Conduct OSSEs to
• 1) evaluate the impact of the DWL measurements
  on the forecasts of hurricanes and winter storms
• 2) determine the minimum requirements of DWL
  measurements in improving the hurricane intensity
  forecast.