Meetings at RAL - Friday 7 July and Monday 10 July, 2000



Meetings were held at RAL between:

(1) Fred Prata, Andy Harris (UK Met. Office) and Andrew Birks (RAL) concerning the AATSR LST ATBD.
(2) Fred Prata and Sarah Watkin (Uk Met. Office) on satellite detection of volcanic ash,
(3) Fred Prata and David Smith (RAL) on ATSR-2/AATSR cal/val,
(4) Fred Prata and John Delderfield (RAL) on the extended range facility of the ATSR-2/AATSR for measuring extreme surface temperatures,

In addition, the following short discussions took place:

(5) Fred Prata and Chris Mutlow (RAL) on the planned visit to RAL by Peter Turner,
(6) Fred Prata and Nigel Houghton (RAL) on the Turner et al. Letter to IJRS,
(7) Fred Prata and Peter Minnett (RSMAS) on the use of stirling cycle coolers for FT-IR and on theoretical considerations concerning spectral resolutions required for tropospheric sounding of O₃.

Summaries

• [1] FP to circulate minutes and action items arising from LST discussion. The main ones being:
  • Recommendations will be sent to DETR for Andy Harris to perform some simulations to investigate emissivity effects.
  • A recommendation will be made to use of the visible/1.6 mm channels for biome identification and cloud detection as part of the LST algorithm.
  • The daytime and nighttime algorithms for LST generation will be different because daytime biome information cannot be carried forward for use on the nighttime data.
  • The AATSR Test data v7 will be acquired and used to test the LST algorithm.
  • A new fractional vegetation cover field determined from the visible channels will be specified in the LST daytime data product. Both single-pixel (F=0 or 1) and 50 x 50 pixel fractional cover will be generated.
• [2] The UK Met. Office are a designated Volcanic Ash Advisory Centre (VAAC) and have requested information from CSIRO on the use of the AVHRR split-window channels for ash detection. Sarah Watkin has used some satellite data sent by me to study the effectiveness of the algorithm. She gave me a report and discussed issues arising from it. She had noticed that the 3.7 mm channel might have some potential for ash detection at night and showed me a convincing example. The recent eruptions from Hekla (Iceland) have hastened the UK Met. Office's research into this hazard.
• David Smith described his recent cal/val inter-satellite comparisons at desert and ice-covered sites. He gave me a draft paper summarising recent results which is being prepared for journal submission. We discussed our collaborations on the ENVISAT proposal for MERIS/AATSR cal/val and talked about collating cal/val results for the visible channels of the ATSR-2.
• John Delderfield described the auto-gain control loop for the calibration of the ATSR-2/AATSR thermal channels. We discussed the possibility of offsetting the counts by some amount to allow higher temperatures to be recorded. Dave Smith has been asked to send me a plot of counts vs. temperature to investigate the impact of an offset change on the lowest and highest temperatures to be recorded. I gave a copy of my recent Technical paper on this issue to John Delderfield.
• Chris Mutlow was very pleased to hear of Peter Turner's proposed RAL visit. He has asked if Peter Turner can suggest dates in August for his visit so that coordination between Peter, Chris and Nigel Houghton can take place.
• Nigel Houghton will email Peter with regard to his draft Letter to IJRS.
• Peter Minnett described the M-AERI stirling cycle cooler arrangement and will email manufacturer details to FP. Peter indicated that no problems had been experienced due to cooler noise. Peter also described his work on temperature/moisture profiling using ground-based FT-IR (M-AERI) at 0.5-1.0 cm^-1. Clive Rodgers has completed some theoretical calculations for tropospheric ozone retrieval that suggest accuracies of 20% might be possible. Better accuracy is expected for the 0.04 cm^-1 resolution of the new CSIRO FT-IR.

Fred Prata

11 July, 2000.