GOES Aviation Products in AWIPS

1
GOES Aviation Products in AWIPS
Short-term Prediction Research and Transition
(SPoRT) Center Training Module

• February 2007

2
NASAs SPoRT Center
Mission Apply NASA measurement systems and
unique Earth science research to improve the
accuracy of short-term (0-24 hr) weather
prediction at the regional and local scale

• Research to Operations -- NASA and Southern
  Region weather forecast offices
• testbed for new products to operations
• training modules and science sharing sessions
• product assessments of impact
• Focus
• NASA EOS satellite observations
• modeling and data assimilation
• nowcasting and lightning

3
GOES Aviation Products in AWIPS
Objective Describe the NESDIS GOES aviation
research products available in AWIPS in advance
of their operational implementation.

• Outline
• Motivation
• Product description
• Examples
• References and links

4
Motivation

• Products require thorough testing before
  dissemination via AWIPS
• In a testbed mode, products can be made
  available ahead of time
• This allows the forecasters to evaluate the
  products
• This testbed approach provides advanced exposure
  and training to the forecaster.
• This training module will
• describe the experimental aviation products
  available to selected offices in AWIPS
• describe how to access and interpret them in AWIPS

5
Benefit of Products to Forecasters

• Products are available hourly
• Cloud and fog properties can be descriminated
• Additional information from these products help
  the forecasters awareness of the current
  environment and can also be used when producing
  TAFs
• In the future, these products will be widely
  disseminated to all WFOs

6
GOES Aviation Products

• The four GOES aviation products, developed by
  Gary Ellrod of NESDIS, are
• icing mask of region where aircraft icing may
  occur
• icing height maximum height of icing above
  surface
• fog depth thickness or depth of fog
• low cloud base height of cloud base above
  ground surface

These experimental products are produced hourly
by NESDIS from the Imager or Sounder on the
GOES-12 satellite at 4 km resolution.
7
Access to Aviation Products in AWIPS

• Aviation products in D2D
• access through the Satellite menu
• default enhancement curves
• correspond to office projections at 4 km
• data available hourly

8
Aircraft Icing
9
Icing Mask and Height

• Basic criteria for aircraft icing
• liquid phase clouds with temperatures in the 0
  to -25 C range
• large droplet diameters (gt 50 µm)
• upward motion to replenish the available
  supercooled water
• large liquid water contents
• long exposure to icing conditions during flight
• GOES satellite data can be used to estimate
• cloud phase
• cloud top temperature
• cloud drop size and liquid water content

(WMO 1954 Hansman 1989 Schultz and Politovich
1992).
10
Detecting Regions of Aircraft Icing

• Are super-cooled drops present? 248 K lt T11
  lt 273 K
• Is water phase present?
• night T3.7 - T11 lt - 2 K
• day T3.7 - T11 gt 0 K ----
  dependant on thickness of
• clouds with use of visible data

• Strengths
• POD 55-70
• FAR 25
• 4 km (Imager) product
• Limitations
• detection obscured by high clouds
• only a threshold -- no estimate of amount of icing

11

Icing Enhanced Cloud-top Altitude Product
(ICECAP)
If icing is possible, assign a height to the tops
of the super-cooled clouds.
Use cloud-top pressure/height from corresponding
GOES Sounder data

• mixture of CO2 slicing and IR assignment
  techniques
• icing height given in units of thousands of feet

12
Fog Detection and Vertical Thickness (depth)
13
Fog DetectionVariations in Channel Emission

• Night-time differences
• T11 T3.9 gt 0 K fog

Emissivity differences between the 11 and 3.9 µm
bands are used to determine the fog depth.
Figures courtesy of Gary Ellrod
This technique can be used not only on GOES
satellite imagers, but also MODIS (Terra and
Aqua) and VIIRS (on NPOESS).
An example which validates the fog depth product
against observations is shown at the right.
14
GOES Fog Depth Product in AWIPS
Colors indicate depth of fog, and non-fog or
middle/high cloud regions are denoted in shades
of cyan.

• Limitations
• sub-pixel clouds add to the uncertainty of the
  fog depth
• not applicable in multi-layer cloud regions
• product uncertainty over non-vegetated (low
  emissivity) surfaces
• only valid at night

15
Low Cloud Base Estimation
16
Low Cloud Base
Instrument Flight Rule (IFR) ceilings (lt 1000 ft)
are likely to occur when T11 Tsfc lt 4 K Red
regions indicate the likelihood of ceilings lt
1000 ft green for ceilings above 1000 ft. Cyan
shades highlight regions of high clouds.

• Strengths
• POD 70
• FAR 10
• Limitations
• sub-pixel clouds add to the uncertainty of the
  cloud base estimates
• not applicable in multi-layer cloud regions

The POD and FAR statistics are based on more than
1500 cases (Ellrod 1996).
17
Summary of GOES Aviation Products
Icing Mask Icing Height Fog Depth Low Cloud
Base Hourly Hourly 15 min. Hourly Night-ti
me Night-time all products are available at
4 km resolution
18
Additional Information -- SPoRT

• SPoRT Program
• http//weather.msfc.nasa.gov/sport - main SPoRT
  web page
• SPoRT Satellite Observations
• http//weather.msfc.nasa.gov/sport/sport_observati
  ons.html - real-time data from MODIS and AMSR-E
• GOES Products for SPoRT
• http//weather.msfc.nasa.gov/goesprod/ - GOES
  products produced for SPoRT including NESDIS
  aviation products

19
Additional Information -- Aviation Products

• COMET Aviation Training Resources
• MetEd Module http//meted.ucar.edu/topics_avi
  ation.php
• Fog and Low Cloud http//meted.ucar.edu/dlac/
  website/expsat.htm
• Web-based Products
• NESDIS - Operational Products Development Branch
• Aviation Products
• http//www.orbit.nesdis.noaa.gov/smcd/opdb/av
  iation/icg.html
• Cloud and Fog Products
• http//www.orbit.nesdis.noaa.gov/smcd/opdb/av
  iation/fog.html
• NWS - Aviation Weather Center (AWC)
• Forecast Icing Potential (FIP)
  http//aviationweather.gov/exp/fip/
• Current Icing Potential (CIP)
  http//aviationweather.gov/exp/cip/

20
Additional Information -- References

• Brown, B., 1996 Verification of in-flight icing
  forecasts Methods and issues. FAA Intl. Conf. on
  Aircraft Icing, Springfield, VA, May 6-8, 1996.
• Ellrod, G. P., 1995 Advances in the detection
  and analysis of fog at night using GOES
  multispectral infrared imagery. Wea. Forecasting,
  10, 606-619.
• Ellrod, G. P., 1996 The use of GOES-8
  multispectral imagery for the detection of
  aircraft icing regions. Preprint Volume, 8th
  Conf. on Satellite Meteorology and Oceanography,
  January 28-February 2, 1996, Atlanta, AMS,
  168-171.
• Ellrod, G. P., 2000 Proposed improvements to the
  nighttime GOES fog product to improve ceiling and
  visibility information. Preprint Volume, 10th
  Conf. on Satellite Meteorology and Oceanography,
  9-14 January, 2000, Long Beach, AMS, 454-456.
• Hansman, R. J., 1989 The influence of ice
  accretion physics on the forecasting of aircraft
  icing conditions. Preprint Volume, 3rd Intl.
  Conf. on the Aviation Weather System, January
  30-February 3, 1989, Anaheim, AMS, 154-158.
• Schultz, P. and M. Politovich, 1992 Toward the
  improvement of aircraft-icing forecasts for the
  continental United States. Wea. Forecasting, 7,
  491-500.
• Vivekanandan, J., G. Thompson, and T. F. Lee,
  1996 Aircraft icing detection using satellite
  data and weather forecast model results. FAA
  Intl. Conf. on Aircraft Icing, Springfield, VA,
  May 6-8, 1996.
• WMO, 1954 Meteorological aspects of aircraft
  icing. WMO Tech. Note No. 3, WMO - No. 30. TP9,
  World Meteor. Org., Geneva, 18 pp.