# Presentation: 342169

## AMSU-A Geolocation

- Thomas J. Kleespies
- NOAA/NESDIS/ORA
- 9 August 2005

## AMSU-A over Red Sea

- 1) AMSU-A2    channel  1  23.7GHz
- 2) AMSU-A1/2 channel  3  50.3 GHz
- 2) AMSU-A1/1 channel 15 89.0 GHz
- Animation reveals a shift between the A2 and A1
- Which is correct?

## Slide 3

## Slide 4

## Slide 5

## Chan 1&15 Animation

- View in Slide Show
- Go to another slide to stop

- Chan 1&3 Animation
- View in Slide Show
- Go to another slide to stop

## Chan 1&15 Animation

- View in Slide Show
- Go to another slide to stop

## Chan 3 &15 Animation

- View in Slide Show
- Go to another slide to stop

## Ascending/Descending node brightness temperature difference

- Makes use of the fact that ascending node views are mostly daytime (surface hot) and descending node views are mostly nighttime (surface cold), _but ocean surface temperatures unchanged_
- Brightness temperatures binned and averaged for each node in 0.5x0.5 deg lat-lon boxes
- Asc minus Des node brightness temperatures differenced and displayed.
***If there is an alongtrack negative offset, northern coastlines will have a cold edge, and southern coastlines will have a warm edge***.
***If there is a negative crosstrack offset the western coastlines will have a cold edge and the eastern coastlines will have a warm edge***
***The reverse of the above is also true***
- _Zoom in to Europe clearly demonstrates this_

## AMSUA18 05152-05172 Channel 1

- What we mean by northern
- southern, eastern and
- western coastlines

- Southern Coastline

- Northern
- Coastline

- Western
- Coastline

- Eastern
- Coastline

## AMSUA18 05152-05172 Channel 15

- Southern Coastline

- Northern
- Coastline

- Western
- Coastline

- Eastern
- Coastline

## AMSUA18 05152-05172 Channel 1

- Zoom in on Europe
- AMSU-A2 appears to be
- geolocated negative alongtrack
- and negative crosstrack

- North Cold

- South Warm

- West Cold

- East Warm

## No Obvious 

- No Obvious
- Red/Blue coastlines

- Zoom in on Europe
- AMSU-A1-2 appears to be correctly geolocated

## AMSUA18 05152-05172 Channel 15

- Hint of
- West Warm

- Hint of
- East Cold

- Hint of
- North Warm

- Hint of
- South Cold

- Zoom in on Europe
- AMSU-A1 appears to be
- geolocated slight positive
- alongtrack and slight positive crosstrack

## Conclusions

- AMSU-A1/1 appears to be geolocated slight positive alongtrack and slight positive crosstrack
- AMSU-A2 appears to be geolocated negative alongtrack and negative crosstrack
- AMSU-A1/2 appears to be geolocated correctly
- Unknown whether it is pointing or navigation
- Bennartz study will refine magnitude of offset.

## MHS Geolocation

- Thomas J. Kleespies
- NOAA/NESDIS/ORA
- 9 August 2005

## MHS over Red Sea

- MHS channel H1 89GHz
- MHS appears to be shifted several pixels alongtrack
- Closeup reveals it to be approximately 1-2 pixels

## MHS18 CHANNEL H1 June 13

## MHS CHANNEL 1 JUNE 13

- Zoom in on Red Sea/Gulf of Aden

## Ascending/Descending node brightness temperature difference

- Makes use of the fact that ascending node views are mostly daytime (surface hot) and descending node views are mostly nighttime (surface cold), _but ocean surface temperatures unchanged_
- Brightness temperatures binned and averaged for each node in 0.5x0.5 deg lat-lon boxes
- Asc minus Des node brightness temperatures differenced and displayed.
***If there is an alongtrack positive offset, northern coastlines will have a warm edge, and southern coastlines will have a cold edge***.
- _Zoom in to Europe clearly demonstrates this_

## Northern Coastline

- Southern Coastline

- Southern Coastline

- What we mean by northern
- and southern coastlines

## North Warm

- South Cold

- South Cold

- South Cold

- Zoom in on Europe

## Conclusion

- MHS geolocation is mislocated in positive alongtrack direction 1-2 pixels
- Unknown whether it is pointing or navigation
- Bennartz study will refine magnitude of offset.

## Preliminary Results of Bennartz StudyCorrection necessary to match coastlines

- *

- * Confirms above results

- *

- *

- *

## AMSU-A Scan Biases

- Thomas J. Kleespies
- 9 August 2005

## Methodology

- June 1 – June 22
- Earth scene brightness temperatures binned as function of scan position
- 40N – 40S
- Ocean only (avoiding coastlines as well)
- Precipitation screening using Grody Algorithm
- Mean brightness temperatures differenced pairwise left – right
- Ascending: solid line, descending: dashed line

## Mean Brightness Temperature as a Function of Scan Position

## Pairwise Left-Right Side Brightness Temperature Difference

## Conclusions	

- A2 left side appears warmer than right side
- A1 right side appears warmer than left side by ~ 1 deg – varies by channel
- Window channels display ascending/descending disparity
- Sounding channels ascending/descending behavior consistent

## MHS018MHS Scan Biases

- Thomas J. Kleespies
- 9 August 2005

## Methodology

- June 1 – June 22
- Earth scene brightness temperatures binned as function of scan position
- 40N – 40S
- Ocean only (avoiding coastlines as well)
- Precipitation screening using Grody Algorithm
- Mean brightness temperatures differenced pairwise left – right
- Ascending: solid line, descending: dashed line

## Mean Brightness Temperature as a Function of Scan Position

## Pairwise Left-Right Side Brightness Temperature Difference

## Conclusions

- Window channels ambiguous: ascending and descending portions of orbit have opposite signature
- Sounding channels show a slight bias (few tenth degree) with the right side being warmer