Joint
Airborne IASI Validation Experiment (JAIVEx) at UW-Madison SSEC/CIMSSFrom Bob Wells (FAAM BAE Flight Operations Manager)
The science team had a long session to discuss possible operations without METOP next week and several instrumental and data odds and ends were addressed.
Saturday is a “Hard Down” day with no access to the aircraft.
From Jonathan Taylor (AIRES Scientist PI):
With the ongoing problems with IASI I wanted to cheer everyone up with news of the excellent data we have gathered so far.
The FAAM BAe146 and the WB-57 have conducted two excellent flights coordinated with the Metop satellite.
The first flight took place coincident with the 0335Z 19th April 2007 overpass of Metop overhead the DoE ARM site in Oklahoma. It was a night time flight and the sub-satellite track of IASI was within 2nm of the ARM central facility. The weather conditions were excellent with totally cloud free conditions prevailing during the flight. The WB57 flew the NAST-I, NAST-M and S-HIS instruments operating at 57,000ft flying a pattern up and down the sub-satellite track. At the same time the BAE146 flew runs at 4000ft (the lowest permitted altitude in that area at night time) and profiled up to 30,000ft before flying at 30,000ft along the sub-satellite track exactly at the overpass. During the overpass time all instruments worked well and the BAe146 launched 11 dropsondes to characterise the temperature and water vapour column. In addition the BAe146 measured the ozone and carbon monoxide profiles in the area. The extremely good coincidence of the WB-57 data and the BAe146 along with the valuable data from the ARM site will make this an invaluable data set for validating the performance of IASI. The atmospheric structure was complex with a moist but cloud free boundary layer – a real challenge for radiometer retrievals.
The second flight took place over the Gulf of Mexico to the South East of New Orleans coincident with the 03:11Z 20th April 2007 overpass of Metop. The FAAM Bae146 took off from Houston and landed briefly at New Orleans to refuel allowing maximum endurance over the area of interest for the overpass time. The WB-57 operated again at 57,000ft with the NAST-I, S-HIS and NAST-M instruments. The BAE146 started the scientific sortie with two runs at 1000ft above the ocean each of 50mins duration. It was a night flight again and the only visible features were the hundreds of oil rigs with their flares and lighting illuminating the ocean surface like a Christmas tree. During these low level runs the ARIES instrument on the BAE146 was used to measure the sea surface temperature which is highly variable in this area showing marked step changes of 1 degree or more over very short distances. The ARIES instrument was also used to measure the down welling radiation at this level which helped with the characterisation of the atmosphere. These measurements of the downwelling radiance spectra, which we could look at in detail during the flight, showed the presence of scattered cumulus, altostratus and cirrus at the Southern end of the run whilst the northern end of the run was totally cloud free. Following the low level runs the BAe146 profiled up through the atmosphere to 33,000ft measuring the state of the atmosphere. The thermodynamic structure was very unusual. The boundary layer was moist up to around 5500ft and then we entered a particularly dry layer with dewpoint depressions approaching 60 degrees Celsius. At 23000ft we entered a moist layer with dew point depressions of only 2 to 5 degrees but there was no cirrus detected by any of the instruments. This very moist layer was 10,000ft thick and it was only at the very top of the layer that we found the cirrus cloud. I have never seen such a deep moist layer at high altitudes without there being cirrus present. During the satellite overpass run the BAE146 and WB-57 flew coordinated runs backwards and forwards along the sub-satellite track. The BAe146 launched 11 dropsondes with 4 dropsondes staggered vertically through the atmosphere at the exact overpass time. All of these dropsondes showed very consistent thermodynamic structure. Whilst at high level the Bae146 sometimes penetrated thin cirrus clouds allowing the microphysics to be characterised. ARIES spectra looking down through the atmosphere showed that the lower level cloud observed earlier had moved away. We will have to look carefully at the Metop data but it is likely that there will mainly be thin cirrus in the IASI fov but we hope that some of the breaks are large enough for clear sky spectra to be measured. All in all this was an excellent flight with some very interesting data from the WB57 and the Bae146 which should keep us busy for some time.
We are all now busy analysing these data and hope to be able to circulate some initial intercomparisons between Metop and the airborne interferometers sometime over the weekend.
Despite the news that Metop has had some difficulties spirits remain high and everyone awaits the return of a fully functional IASI in order that we can go out and gather some more data.
In the meantime we are considering doing a coordinated flight of the WB57 and BAe146 to look at sub-tropical cirrus in coordination with the Aqua satellite, Calipso and Cloudsat (the A-train).
From Bob Wells FAAM BAE Flight Operations Manager:
Flight B285 to observe the METOP overpass over the Gulf of Mexico with the NASA WB57 was billed as FAAM’s first attempt at a 3-sector science flight and had taken a lot of effort to set up. Two refuelling stops were arranged at New Orleans.
The science work along the sub-orbital track was very interesting and successful.
12 dropsondes worked well (minor problems with a couple). Some areas were clear sky and in other places there were scattered clouds of various types. Steep sea-surface temperature gradients were observed at one point and some in-situ cloud physics data was recorded so, altogether, this should produce an extremely valuable IASI validation dataset.
There was just enough fuel remaining at the end of the (slightly-modified) science flying to recover directly to Ellington and so avoid a second refuel at New Orleans.
Soon after the team had hit the sack came news of a major problem with the METOP satellite and Principal Investigator Jonathan Taylor was woken by a call from EUMETSAT.
At the time of writing (1700Z 20th April) it sounds as though IASI will be out of action for something like a week. This is likely to reduce the amount of flying FAAM attempts in this period but there are possibilities of work with the Houston Plume and with the AQUA satellite.
Hopefully there will be a clearer programme to present to the team at the hotel at 1800L meeting on Sunday.
This is a useful tool:
http://flightaware.com/live/flight/NASA926
We don’t have the REVEAL system working with S-HIS yet (there have been other pressing issues to date), and have had some issues getting NAV data post flight in a timely manner.
Joe
From Allen Larar NAST-I Scientist
We are flying a mission tonight over the OK CART site region, coordinated
with the Metop 0335 GMT (19 Apr) overpass. RTB between 1-2 AM expected.
I will be leaving town for a few days; outlook for the next several
days is as follows:
19 Apr (Thurs) 7:15 PM (local) takeoff (night flight; Metop; GOM)
20 Apr (Fri) no flight
21 Apr (Sat) down day
22 Apr (Sun) down day
23 Apr (Mon) possible day *or* night flight (night most likely)
24 Apr (Tue) possible day *or* night flight (night most likely)
25 Apr (Wed) no flight
26 Apr (Thu) no flight
27 Apr (Fri) day flight
28 Apr (Sat) possible day *or* night flight
29 Apr (Sun) day flight
From Bob Wells FAAM BAE Flight Operations Manager
Flight B284 took off into the setting sun and was joined by the NASA WB57 for a very successful sortie with clear skies over the Oklahoma ARM site and under the METOP satellite.
Another night flight (i.e. no SWS or video cameras!) has been planned for Thursday night - Friday morning with two refuelling stops in New Orleans. This will observe the METOP pass over the Gulf of Mexico.
Saturday has been declared a hard down day and there will be no flying on Sunday.
From Bob Wells FAAM BAE Flight Operations Manager
Tuesday was a no-fly day.
The SATCOM phone problem was raised with the service provider, Stratos, but as yet there is no indication that it has been fixed.
A lot of planning was undertaken in an attempt to exploit the 2007/04/19 03:35Z METOP pass directly over the ARM ground observatory. Three possible sorties have been devised and the decision on which one of these to fly will be taken by Houston noon Wednesday in light of the latest cloud forecasts. All three briefs involve a landing in the wee small hours of Thursday.
Partly as a consequence of this Stuart Newman will be investigating the possibilities of another overnight METOP mission Thursday-Friday night which may involve a refuel (possibly at Mobile, Alabama).
It is highly probable that Saturday and Sunday will be declared ‘down days’ so avoiding many constraints on the programme from crew-hour limitation considerations. There will be no suitable satellite passes on these days and wind forecasts do not look good for another Houston Plume jaunt.
Radiosondes are available within link on Data Archive at:
(From Bob Wells FAAM BAE Operations Manager)
Flight B283 on Monday was very successful. Both the 146 and the WB57 enjoyed clear-sky conditions and positioned under a pass of the AQUA satellite near the ARM ground observatory in Oklahoma.
(The flight track of the WB57 can be found at http://flightaware.com/live/flight/NASA926)
A refuelling stop at Oklahoma City went smoothly.
When performing the pre-flight checks, discovered one of the broadband radiometers full of water. Fortunately he was able to fit a spare sensor for the flight. During the flight the TWC instrument gave an error indication but later, apparently, resumed normal service. The optical discs which record data on the HORACE system gave several problems and are apparently showing the signs of senile dementia.
The ground team spent most of the day planning a METOP Pass flight for Tuesday but, late in the day, the flight was cancelled because of the weather forecast (cloud, rain and thunderstorms). Tuesday will therefore be a down day.
(From Allen Larar - WB-57 Scientist)
We appear to have had a
successful flight Monday (20070416), and have canceled the
flight planned for today due to heavy weather likely
over the OK/CART site region.
We had clear sky conditions for our tracks in OK today, and
had both aircraft at or near the CART site during the
Aqua overpass, with nominal instrument operations reported.
Current status (from Allen Larar):
Today (16 Apr). Flight scheduled over CART site, coordinating
with Aqua 1952 GMT overpass. BAE 146 will be flying low-level
runs, ascents/descents, and following a high-altitude s-n line
at time of overpass (CART site ~ center of line). WB-57 takeoff
around 1220 (local) and will be flying at high-altitude same
line with time/space coordination with BAE 146 at overpass
time. Around 30 mins after overpass, a/c will leave the target
area; BAE 146 will RTB while WB-57 will run a line to achieve
clear sky over GOM prior to descent into HOU.
Tues (17 Apr). Flight plan over OK region (a large box with
CART toward eastern side, and Metop sub-satellite toward western
side). Metop overpass is 1636 GMT. This will focus on sampling
a varying clouded environment. We will monitor weather and
IASI scan mode changes and re-consider this flight later.
Wed (18 Apr). Two scenarios under consideration: day flight
catching Metop & Aqua over CART site region, vs night flight
aiming at Metop alone over clear-sky GOM. Decision expected
Tues AM regarding desired option.
Thurs (19 Apr). Night flight over OK to catch both Metop & Aqua
overpasses.
Today’s weather over DOE ARM site looks fine. Only fly in ointment is possible cirrus contamination from the southwest. At this point, the mass of clouds remain SE of the area of interest:
http://cimss.ssec.wisc.edu/jaivex/wx-prods/vis.html
but the CRAS forecast indicates the cloudiness will become more extensive with time:
http://cimss.ssec.wisc.edu/model/realtime/cras20_Gulf/cttpn.html
as low develops over the front range of the Rockies over night.
Weather conditions over Oklahoma deteriorate very rapidly overnight with extensive precipitation developing by Noon Local on 17 April 2007:
