GPM Continental Supersite: Requirements

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• GPM Continental Supersite Requirements Concept
• Provide physical validation and error statistics
  for algorithms demand error statistics for all
  measurements at supersite. The latter is a
  substantial issue in and of itself. The ground
  data are obviously NOT error free!
• Provide data so that algorithms can develop
  diagnostics to identify sources of error.
• Perform basic science. Initial thrust would be
  to identify relationship between large scale
  variables and precipitation regime/precipitation
  structure.
• Science thrust would relate large scale
  parameters (low-level wind direction, CAPE, etc.)
  to precipitation type (convective, stratiform,
  ice-based, warm rain, etc.). Algorithms would
  use this information to decide on best
  parameters to use. This is an important point
  since TRMM has taught us that biases in the
  satellite algorithms are not only due to
  systematic algorithm errors, but also by changing
  cloud properties. There is a need to understand
  and describe these changing cloud properties
  (rainfall regimes) so that these types of errors
  can be minimized. This information will serve as
  guidance for algorithms. For example,Z-R
  relationship ALPHA is used region A in season B.
• Provide motivation for field measurements to
  address specific algorithms problems, biases,
  etc.

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GV and Algorithm Team Interaction
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Regime Identification Example TRMM-LBA
TRMM-LBA Regime ID Low-level zonal wind
TRMM-LBA Regime ID Lightning Flash Count

• Regime ID based on NCEP zonal wind direction
  (trends similar to A-hill)
• Metric to distinguish vertical structure
  characteristics

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The Evolution of Rain-type Classification
Early Radars 40s
C/S Separation 50s-present
Convective Stratiform
PDF(ZDR)
LBA E/W Climate Regimes (Petersen et al 2002)
Vertical Structure Classification (Present Work)
The Red and purple curves correspond to two
distinct rain-type classes found in both the East
(solid) and West(dashed) regimes in LBA.
Easterly Westerly
PDF(ZDR)
ZDR (dB)
ZDR (dB)
ZSFC 42 ? 2 dBZ

• Classifying rainfall by vertical and horizontal
  structure reduces climate regime dependent biases
  in global precipitation products as well as
  random errors

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Timeline for GPM Continental Super-Site
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Proposed GPM Continental Supersite
ARM-CART site, Ponca City, OK
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Instrumentation at the DOE ARM-SGP Site

• Aerosols
• Continuous ground based monitoring (AOS),
  occasional aircraft profiling
• Atmospheric Profiling
• Radiosonde site (up to 4 per day)
• Column water vapor and cloud liquid water (MWR)
• Vertical profiles of water-vapor, cloud- and
  aerosol-related quantities (Raman Lidar)
• 50 and 915 MHz Wind Profiler and RASS
• Clouds
• 35 GHz vertically pointing radar (MMCR)
• Cloud base height (Vaisala Ceilometer)
• Cloud base and PBL height (Micropulse Lidar)
• Surface Energy Flux
• Eddy Correlation Flux, Surface Bowen Ratio
• Surface Meteorology
• 60 m meteorological tower, precipitation and snow
  depth gauges

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GPM Continental Supersite Surrounding
Observational Network
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GPM Continental Supersite Deployable
Instrumentation
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GPM Continental Supersite Sampling Issues

• How does the PDF of snow change temporally and
  regionally?

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Near-Term Action Items Related to GPM Continental
Supersite Discussed at TRMM Meeting (29 October
2003)

• GPM validation should build on concept of TRMM
  GVprovides roadmap
• TRMM told us that there were intrinsic errors in
  algorithms plus errors attributable to physics of
  rain systems
• Discussed concept of rainfall regime can
  expected physics of precipitation in footprint
  of TRMM/GPM/ground based radar (Do, Z profile),
  be described or linked to routinely available
  data like low level winds, reconstructed
  soundings, aerosol observations, etc?
• Regime classification would provide guidance to
  algorithms
• Regime D------use this Z-R relationship, etc.
• Recommended that work on regime classification
  continue.

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Action Items (cont)

• Conduct a design study that would lead to a rain
  standardat the OK ARM CART site for use in the
  pre-GPM era consisting of dense gauges,
  distrometers, and a dual-wavelength profiler.
  This would be our precipitation metric. Involve
  polarimetric radars for detailed intercomparison
  as these radars will be used in other locations
  for GV within the GPM era. Radars are transfer
  standard. S and X-band polarimetric systems are
  required.
• Assess the role of the C. Florida gauge/radar
  network as well as the Wallops Is. rain measuring
  facility in both the GPM pre-flight era and
  mission era. These sites have excellent
  capabilities and would provide for additional
  precipitation regimes to be identified and
  quantified. Also, when same regime is identified
  between two sites, do they have the same physical
  characteristics (rain pdf Do, etc)?

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COLORADO FRONT RANGE PILOT PROJECT May-June 2004

• Collaborative Effort
• CSU
• NOAA/AL
• NOAA/ETL

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PILOT PROJECT GOALS

• Dual-wavelength radar DSD and rain rate estimate
  intercomparison, validation, and error
  characterization.
• Profiler demonstration in the supersite concept.
  
• Rain rate and drop size distribution
  characterization in the context of supersite
  observations, rainfall regimes.
• Demonstration of the regime identification
  concept.

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CSU-CHILL Operations Summary
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21 May 2004 Rain Hail Observations
(Brooks Martner photo)
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CHILL Observations 0023 UTC
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XPOL Observations 0024 UTC
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(No Transcript)
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BAO Profiler Site
X-band RHI Scan Raw Reflectivity
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Profiler Spectra from BAO Tower 0054 UTC
S-Band
449 MHz
Possible evidence of 2 distinct microphysical
processes
clear air peak
precipitation peak
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29 May Platteville Profiler-Disdrometer
Measurements
S-Band vs. J-W Disdrometer dBZ
S-Band Ze, Vr, and SW
10 km
CHILL RHI _at_ 1922 UT
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Murpheys Law of Field Programs Precipitation
Events Will do Their Best to Avoid the Ground
Instrumentation