# Presentation: 501346

## Satellite Remote Sensing of  Aviation Hazards

- Gary P. Ellrod , CCM*
- NOAA/NESDIS-retired
- Granby, CT

- Aviation Weather Users Workshop, Nov 18-19, 2008
- Islip/Macarthur Airport, NY

- * AMS Certified Consulting  Meteorologist

**Notes:**
Satellite remote sensing is critical to aviation due to the vast data-void areas over which aircraft must fly. This talk is an overview of how we can use satellite data and products to detect significant aviation weather hazards or conditions.

## Outline

- Current capabilities of satellite data
- Fog and low clouds
- Inflight icing
- Turbulence
- Thunderstorms (initiation, convective gusts)
- Volcanic ash
- Future improvements (GOES-R)

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Basic outline of talk.  Will close with a summary of expected new spacecraft and their capabilities during the next ten years.

## U.S. Weather Satellites

- Polar (low orbit) (NOAA-18 / METOP-A)
- 1 km resolution
- 4 looks per day
- 6 channels
- Geostationary (GOES-11/12)
- 4 km IR, 1 km visible
- 15-30 min frequency
- 5 channel Imager
- 19 channel Sounder (10 km), hourly over CONUS

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Summary of the two primary U. S. operational weather satellite systems and their observing capabilities. Polar satellites have global coverage at high resolution but infrequent revisits. Geostationary satellites have hemispheric coverage at frequent intervals with moderate resolution.

## Nighttime Fog Detection Using GOES Multi-spectral Image Data

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Temperature slice across line A-B in right hand images showing the 10.7 and 3.9 um IR channel data across a region of cirrus, clear skies, and low stratus clouds.  The stratus clouds are highlighted best by the difference in the two channels (bottom image in right panel).

## Fog in the Northeast: 14 June 2001 

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Examples of features observed in nighttime fog images using a brightness temperature difference of 2C (CH4 – CH2). False detects are caused by low emissivity desert soils. Differences between very low fog/stratus and high-based stratiform are subtle.

## GOES Low Cloud Base Product

- Based on GOES 11m-3.9 m and surface minus GOES cloud top temperatures (now available on AWIPS)

*Red areas show where cloud bases <1000 ft are likely, green areas > 1000 ft, blue are cirrus clouds.*

**Notes:**
Example of cloud base product over the Middle Atlantic states with low ceilings highlighted in red.

## Fog Depth Estimates

- Estimates of fog depth also possible based on 11m-3.9 m temperature difference (to forecast burn off time)

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Estimate of fog depth (left) is based on brightness temperature difference (CH4 –CH2).  Thicker patches of fog tend to persist longer, as shown in right hand GOES visible images.

## Snow and Fog Using Visible Imagery

- Snow

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
It is often difficult to determine the borders of fog during daylight hours.  GOES/NOAA shortwave channels highlight low clouds due to stronger reflectance by water droplet clouds at that wavelength compared with snow-covered surfaces.

## Fog Discrimination with 3.9m Imagery

- Fog Discrimination with 3.9m Imagery

**Notes:**
GOES 3.9 m IR can be used to discriminate stratus clouds from snow cover during daytime.

## GOES Icing Risk Product	

- Multi-channel threshold technique
- Merged with Sounder cloud top heights
- Product available hourly day and night
- Strengths
- Good spatial, temporal coverage
- Good POD (~50-75%), low FAR (~25%)
- Weaknesses
- Obscuration by high clouds
- Unable to distinguish SLD regions

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Capabilities of NESDIS GOES icing potential product.

## GOES Combined Icing + Cloud Tops (‘ICECAP’)Available at: http://www.star.nesdis.noaa.gov/smcd/opdb/aviation/icg.html 

*Icing intensity (3=mod, 4=mod/sev), aircraft type, altitude (feet)*

**Notes:**
Example of GOES-12 ICECAP product showing color-coded cloud tops in regions of potential icing. Pilot reports show intensity, aircraft type, and altitude (ft).

## GOES Water Vapor + IR  Winds

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Strong winds detected by GOES cloud motion in the North Pacific between Hawaii and the U. S. mainland.  Turbulence was reported in the banded cloud regions due to the decelerating flow and deformation.

## Detection of Mountain Waves Using Water Vapor Imagery

- Low and mid-Tropospherice waves
- can be seen in GOES 6.7 m water
- Vapor imagery, but not in IR or
- visible

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Water vapor channel images (6.7 um) can detect mountain wave patterns not seen in visible or infrared.  These waves in western North Carolina were associated with severe low level turbulence below 10 thousand feet. GOES-12 water vapor channel has a resolution of about 5 km at this latitude.

## Total Column Ozone from GOES Sounder

**Stratospheric **
**Intrusion**

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Total ozone product generated by University of Wisconsin CIMSS from GOES Sounder using statistical regression based on 9.7um ozone channel, plus other bands.  Maximum ozone band (green) is associated with Tropopause folding and possible clear air turbulence.

## Convective Initiation

- Critical for air traffic management
- GOES Visible Imagery Applications (boundary interactions, stability, etc)
- Stability and moisture Products from Sounder (Lifted Index, PW, Cinh)
- Automated Nowcast Products
- Convective Initiation (UW-CIMSS and U. of Alabama-Huntsville)

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
GOES products used to determine areas of potential convective initiation.

## Convective Initiation (CI) Product(U. of Ala-Huntsvile/ U. of Wisconsin CIMSS)

- Uses satellite parameters to identify convective clouds:
- IR temp. change
- WV - IR temp. difference
- Cloud motion vectors to advect developing clouds, produce nowcast

- CI valid 2000Z, 4 May 2003

- Radar, 2100Z, 4 May 2003

**Notes:**
GOES Convective Initiation (CI) product (Mecicalski et al 2004) based on multi-spectral cloud mask, time change of satellite IR temperatures, and mesoscale cloud motion vectors (top).  Verifying radar in bottom panel.

## Wet Microburst Severity Index

- Uses GOES Sounder retrieval data
- Based on instability and vertical distribution of moisture (CAPE, dθe/dz)
- Correlates well with observed peak surface wind gusts

*WMSI > 200 indicates wind gusts > 65*
*knots possible. 85 knot gusts were *
*reported at Patuxent River, Maryland*
*at 2100 UTC (*).*

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Potential for high wind gusts based on Wet Microburst Severity Index (WMSI) from GOES Sounder on 14 July 2004.  WMSI developed by Ken Pryor (NESDIS SMCD)

## Composite “Split Window” ImageryMt. Spurr, Sept. 1992, NOAA-AVHRR

- (Schneider et al 1992)

**Notes:**
Notable example of the use of “Split Window” (AVHRR Band 4-5) product in tracking ash cloud from Mt. Spurr eruption across Canada and the U. S. in Sept. 1992.

## International Warning System (VAACs)

- Established by ***International Civil Aeronautical Organization (ICAO)*** in mid-1990’s
- Volcanically active regions source: Smithsonian Inst.

**Notes:**
VAAC network (from ICAO), areas of responsibility, and active volcanic regions (from USGS).  

## Technology OutlookOperational Spacecraft

***Near-Term***
- GOES-N (launched May 2006) through P
- Improved navigation, power to operate through satellite eclipse (Spring, Fall)
***Mid-Long Term***
- NPOESS VIIRS imager (NPP prototype launch in 2010)
- Twenty-two bands at 370 to 740 m resolution
- Includes day/night visible

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Near-term and mid-term improvements expected for operational U.S. spacecraft.

## Technology OutlookOperational Spacecraft

***Long-Term***
- GOES-R Advanced Baseline Imager (2015)
- Sixteen spectral bands
- Resolution: 0.5 km visible, 2 km IR
- Five minute CONUS, 15 min Full Disk
- GOES-R Lightning Mapper
- GOES Hyper-spectral Sounder - ????
- Hyper-spectral capabilities, hourly global coverage
- Good resolution (4 km horizontal, ~1 km vertical)

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Long-term expected improvements to U. S. spacecraft.

## ABI Improvements

**5 Minute Coverage**

- ABI covers the earth approximately five times faster than the current Imager.

**Notes:**
Rapid scan – 7 1⁄2 minutes operationally GOES-R – full disc in 5 minutes

## Imager Coverage in ~30 minutes 

- Imager Coverage in ~30 minutes

|  | Current Imager
(Rapid Scan mode) | Future Imager
(“Flex” mode) |
| --- | --- | --- |
| Full Disk | 0 | 2 |
| Northern Hemi | 1 | - |
| CONUS | 3 | 6 |
| Mesoscale | 0 | 60 |

- Full Disk

- N. Hemisphere

- CONUS

- Mesoscale

**Notes:**
Possible scanning scenario of GOES-R series ABI (right column) compared with current capabilities for sectors shown at bottom.

## IR Resolution – ABI versus GOES-12

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Comparison of simulated 2km GOES-R IR image of thunderstorm complex compared with 4km GOES-12.

## Use of 1.6 m “Near-IR” on ABI

**1.6 ********m**

**Notes:**
A near-IR channel to be deployed on ABI can discriminate low clouds from surrounding snow-covered ground due to lower reflectance of snow at this wavelength.

## Simulated GOES-R Fog ImageBased on AVHRR IR (3.7 m and 11.0 m)

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Example of low cloud image possible from GOES-R imager (simulated using AVHRR).

## GOES-R Icing Product (NASA LARC)

- Explicit parameters from
- GOES (droplet size, liquid
- Water path) can  estimate
- Potential icing severity

**Notes:**
Icing severity index using GOES-12 IR (upper left) is based on explicit cloud parameters, compares well with model-based Current Icing Product (lower right).

## Simulated Water Vapor Imagery (Low, Mid, High) on ABI

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Lower right image simulates a WV band from GOES-R using the MODIS instrument versus observed GOES-12 image.

## Automated Turbulence Detection – GOES-R Water Vapor(U. of Wisconsin – CIMSS)

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
High altitude turbulence nowcast product under development for GOES-R at UW-CIMSS uses a corrected (true) water vapor product, plus high resolution numerical model data to depict likely turbulence caused by tropopause folds (upper fronts).

## Simulated GOES-R Ash ImageBased on MODIS IR, Near-IR, Visible Channels

- Volcanic ash (red)
- Composite of 8.5, 11, 12m channels
- Land (green)
- Near-IR (1.6m)
- Ocean/ice clouds (blue)
- Visible (0.6m)

- Popocatepetl, 20 Dec 2000, 1715 UTC
- Based on data from Terra MODIS

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Example of possible GOES-R volcanic ash product simulated using MODIS data.

## Geostationary Lightning Mapper  (GLM)

**Detects total strikes: in cloud, cloud to  **
**Day/night **_**total**_** lightning (in cloud, intra-cloud, and cloud to ground)**
**Compliments today’s land based  systems that only measures cloud to ground (about 15% of the total lightning)**
**Increased coverage over oceans and land**
**Currently no ocean coverage, **_**and **_**limited land coverage in dead zones**

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Description and two-GOES coverage of total lightning sensor to be deployed on GOES-R and follow-on spacecraft.

## Example from Lightning Imaging Sensor (LIS) 

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Example of how total lightning from the LIS (on NASA TRMM satellite) can provide warnings of developing severe storm over OK.

## Simulations of Low vs High Spectral Resolution Retrievals Geo-I gets <1 K rms for 1 km T(p) and <10% rms for 2 km RH(p) 

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Simulations of possible Hyperspectral Environmental Sounder (HES) retrieval accuracy, based on radiosondes. 
Preliminary HES simulations using the noise specified in the HES Technical Requirements Documents. These simulations were done by Jun Li (UW-CIMSS). It can be seen that, in general, the NWS retrieval accuracy is acquired.
There’s a poster on this topic by J. Li of CIMSS at the 11th Satellite Conference.

## Capability: Vertical Profiling

- BT(K)

**Capability: Vertical Profiling**

- Analysis courtesy of Jun Li, CIMSS.

**Notes:**
High vertical resolution water vapor wind profiles from a geostationary high capability sounder are expected to improve tropical storm track and intensity forecasts. Plus soundings in hurricane eyes and the surrounding environment will help with hurricane monitoring.

Retrieval and image provided by CIMSS/SSEC

## Summary

- Satellite remote sensing is critical in providing needed observations to support aviation warnings and forecasts
- Future instruments will provide excellent opportunities for improved products
- Much work is needed to fully utilize future  deluge of high quality data!

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Summary

## Internet Resources:

- GOES Aviation Products (Imager and Sounder)
- _[http://www.star.nesdis.noaa.gov/smcd/opdb/aviation/](http://www.star.nesdis.noaa.gov/smcd/opdb/aviation/)_*  **(NESDIS)*
- _[http://weather.msfc.nasa.gov/goesprod/](http://weather.msfc.nasa.gov/goesprod/)_* (NASA GHCC)*
- _[http://www.nrlmry.navy.mil/NEXSAT.html](http://www.nrlmry.navy.mil/NEXSAT.html)_* (NRL-Monterey)*
- GOES-R Information
- _[http://www.goes-r.gov/](http://www.goes-r.gov/)_*  **(GOES Program Office)*
- _[http://cimss.ssec.wisc.edu/goes_r/](http://cimss.ssec.wisc.edu/goes_r/)_*  **(UW-CIMSS)*

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY

**Notes:**
Links to realtime GOES aviaton products.

## Acknowledgments

- Slides obtained from:
- Brian Motta (COMET)
- Ken Pryor (NESDIS)
- Tim Schmit (NESDIS)
- William Smith, Jr. (NASA)
- Anthony Wimmers (UW-CIMSS)
- Kris Bedka (UW-CIMSS)

- Aviation Weather Users Workshop, Nov 18-19, 2008 Islip/Macarthur Airport, NY