tamdar alaskan data compiled by ed szoke noaa/cira/gsd 2007 cases comparing tamdar out of anchorage...

TAMDAR Alaskan data compiled by Ed Szoke NOAA/CIRA/GSD

2007 cases comparing TAMDAR out of Anchorage (ANC) and other Alaska airports nearby RAOB cases

• Airports with TAMDAR flights in Alaska• KANC - Anchorage

• The most flights, with several near the nearby 0000 UTC RAOB• KPDU – Prudhoe Bay

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TAMDAR Alaskan data compiled by Ed Szoke NOAA/CIRA/GSD

2007 cases comparing TAMDAR out of Anchorage (ANC) and other Alaska airports nearby RAOB cases

• Airports with TAMDAR flights in Alaska – Horizon airlines• ANC (Anchorage) - the most flights per day, up to 9 TAMDARs within +/- 2 h of 00z• SNP St. Paul Island (PASN) 2 flights; 0022 and 0221 UTC• DUT Dutch Harbor (METAR station PADU) nearest RAOB is to the east at CDB; 2 full flights in and out near 0000 UTC• CDB Cold Bay one flight in at 2132 UTC plus RAOB at CDB; this flight does not leave again until 0510 UTC• DLG Dillingham 2 full flights, nearest RAOB is not too far to the southeast at King Salmon (PAKN)

• Airports with TAMDAR flights in Alaska – Penn Air airlines• ANI (Anika) arriving from ANC at 2030z Departs at 2100z (2017z down and 2048z up on 4 Dec)• CDB (Cold Bay) arriving from ANC at 2110z Departs at 2140z • arriving from ANC at 0530z Departs at 0545z• DLG (Dillingham) arriving from ANC at 1845z Departs at 1915z • arriving from ANC at 0330z Departs at 0400z• AKN (King Salmon) arriving from ANC at 1805z Departs at 1835z • arriving from ANC at 0420z Departs at 0440z• MCG (McGrath) arriving from ANC at 1815z Departs at 1845z ( seems to be missing much of the time, however)

TAMDAR Alaskan data: summary of cases (all compare to 0000 UTC RAOBs

• 7 Oct 07: low in Gulf of Alaska. Down TAMDAR into ANC looks bad.• 8 Oct 07: weaker low a bit farther north; good ANC comparison, RAOB has a bad point!• 9 Oct 07: compact low just sse of ANC; good ANC comparisons.• 10 Oct 07: surface low still in Gulf of Alaska; comparison with ANC good, some RH difference.• 11 Oct 07: surface low in eastern Gulf of Alaska. TAMDARs compare well with each other but not ANC RAOB. • 14 Oct 07: small surface low sse of ANC. Similar to 11 Oct, great TAMDAR agreement, but all drier than ANC.• 17 Oct 07: upper low in Gulf of Alaska with very moist conditions in southern Alaska. Differences with the ANC RAOB that are not easy to explain as both TAMDAR and RAOB head off in the same direction.• 18 Oct 07: similar conditions to 17 Oct. Better TAMDAR agreement with ANC RAOB.• 19 Oct 07: low shifted to far ne Gulf of Alaska with weak winds aloft over ANC. Overall good agreement at ANC• 24 Oct 07: still moist but finally no surface low in the Gulf of Alaska. ANC RAOB and TAMDARs go in different directions, which could explain some lower level differences. ACARS also shown.• 29 Oct 07: low in the Gulf of Alaska with lots of cloudiness southern Alaska coast. Comparison with King Salmon (AKN) and ANC RAOBs. AKN has bad data down low, otherwise both comparisons are good.• 30 Oct 07: Big system south of Aleutians with lots of deep cloud over southern Alaska ahead of low. Detailed comparison with ANC RAOB. Some differences, including winds, are examined. AMDAR soundings seem to lend support to conditions warmer than the RAOB measures.• 31 Oct 07: surface low has moved to the ene and sits right over ANC so lots of variation in short distance from ANC, and this is shown in the TAMDAR comparison with the ANC RAOB. • 2 Dec 07: High-amplitude ridge over Alaska so much different conditions. Comparisons shown with several different Alaska RAOBS, and are generally good, showing subsidence drying and warming.

Alaska area RAOBs

PAFC = Anchorage = ANC

CDB

BRW

YAK

Dutch Harbor (DUT)

Prudhoe Bay

Weather overview: IR image with surface obs for Alaska at 0000 UTC 7 Oct 07.

ANC

Comparison with 0000 UTC 7 October 2007 ANC RAOB.

The 0031z TAMDAR (black)seems excessivelymoist, and also has anodd T profile near 900mb. The 2309z ACARS (not aTAMDAR a/c) has acouple of odd (warm)T points (700 and ~875 mb). The 2324z TAMDAR compares favorably tothe RAOB (this is shown separately inthe next slide).

Comparison with 0000 UTC 7 October 2007 ANC RAOB.

The 2324z TAMDAR (black)compares favorably with the 0000 UTC ANC RAOB.

Weather overview: IR image with surface obs for Alaska at 0000 UTC 8 Oct 07.

ANC

Weather overview: Vis image with surface obs for Alaska at 0000 UTC 8 Oct 07. Small surface low is just off the coast to the sse of ANC.

Comparison with 0000 UTC 8 October 2007 ANC RAOB.

TAMDAR is in reasonable agreementwith the ACARS and the RAOB.

Weather overview: Vis image with surface obs for Alaska at 0000 UTC 9 Oct 07. Small surface low is just off the coast to the sse of ANC.

Comparison with 0000 UTC 9 October 2007 ANC RAOB.

TAMDAR is in reasonable agreementwith the RAOB.

Comparison with 0000 UTC 9 October 2007 ANC RAOB.

The TAMDAR temperature profile isin good agreementwith the two ACARS that are heading in about the same direction.

Weather overview: IR image with surface obs for Alaska at 0000 UTC 10 Oct 07. Surface low is now shifted to the west in the Gulf of Alaska.

Comparison with 0000 UTC 10 October 2007 ANC RAOB.

The 00z RAOB isblack. The 3 TAMDARs head offto the SW while theRAOB goes more tothe south and then east. Nonetheless,good overall agreement in bothTd and T for TAMDAR andRAOB comparison.

Weather overview: Vis image with surface obs for Alaska at 0000 UTC 11 Oct 07. Small surface low is now off the coast to the se of ANC.

Comparison with 0000 UTC 11 October 2007 ANC RAOB.

The 2 TAMDAR aircraft head off in the same direction to the southwest whilethe RAOB would head south then se.Great agreementbetween the 2 TAMDARs but notvery good RH comparison with the RAOB (although thetemperature comparison is good).

Weather overview: IR image for 0000 UTC 14 Oct 07. Small surface low appears to be just off the coast to the se of ANC.

0000 UTC 14 October 2007 ANC RAOB.

The trajectory of theRAOB would be tothe nw.

Comparison with 0000 UTC 14 October 2007 ANC RAOB.

The TAMDAR flights all head offto the sw. Prettygood agreementwith the RAOB downlow but all are drieraob 850 mb.

Comparison of ~0000 UTC 14 October 2007 ANC area TAMDARs.

The 4 TAMDAR aircraft head off in the same direction to the southwest and arein very good agreement with eachother, especially atmid and upper levels.

Weather overview: IR image with surface obs for Alaska at 0000 UTC 17 Oct 07. Very moist conditions with low pressure in the Gulf of Alaska.

Comparison with 0000 UTC 17 October 2007 ANC RAOB.

The RAOB and theTAMDARs in thiscase head off in aboutthe same direction.Very good agreement with the temperature in the RAOB aob ~850 mb. All the TAMDARs are warmerthough then the RAOBat higher levels though.Kind of a mixed agreement with RH at lower levels with a couple of the TAMDARs picking upon the moistening shown in the RAOB just below 900 mb. Two of them (2351 and 2355z TAMDARs) however are quite different both at thelower levels and aloft.Not sure what to makeof this since they are both generally goingin the same direction asthe RAOB.

Comparison with 0000 UTC 17 October 2007 ANC RAOB.

This figure isolates the 2 TAMDARsoundings that are most different from the RAOB. Noticethough that these TAMDARs have better agreement with the temperatureaob 750 mb.

Comparison with 0000 UTC 17 October 2007 ANC RAOB.

Whereas these TAMDARs are allwarmer than the RAOB at the midand higher levels, buthave much better agreement in dew point temperature.

Weather overview: IR image with surface observations at 0000 UTC 18 Oct 07. Very moist again with a surface low in the eastern Gulf of Alaska.

Weather overview: Visible satellite image with surface observations at 0000 UTC 17 Oct.

Comparison with 0000 UTC 18 October 2007 ANC RAOB.

The 0000z RAOB (black) is in goodagreement with all but the 0104z TAMDAR. The RAOB and TAMDARs both head off in aboutthe same direction.

Comparison with 0000 UTC 18 October 2007 ANC RAOB.

The TAMDAR soundings are in verygood agreement witheach other and all head off the the wsw.Not an exact agree-ment with the RAOB(though pretty goodbelow ~900 mb) butnot too far off.

Weather overview: Quite cloudy with surface low over extreme eastern portion of the Gulf of Alaska

Comparison with 0000 UTC 19 October 2007 ANC RAOB.

There is not much wind so the RAOB is probably not far offfrom where the TAMDARs are.Good temperature agreement with the inversion at 875 mb.Overall, there is goodagreement with the moisture profile with the 0020 UTC TAMDAR off by themost.

Comparison with 0000 UTC 19 October 2007 ANC RAOB.

The 0044z TAMDAR is the newone not shown in the previous figure.Good general agreement with the RAOB dew point except too moist aob700 mb, though giventhe amount of cloudspresent the more moist profile could certainly be good.Temperature agreement is quitegood.

Weather overview: Widespread cloudiness but this time surface low is well to the west.

Comparison with 0000 UTC 24 October 2007 ANC RAOB.

The 00z RAOB headsoff to the ene, oppositethe direction of the TAMDARs. This could explain the moisture differences down low, although looking at the satelliteimage it seems it should be opposite to what actually occurs.Higher up the agreement is better with the RAOB.

Note the temperatureprofiles from the TAMDAR are mostlycooler than the RAOB.

Comparison with 0000 UTC 24 October 2007 ANC RAOB.

The 00z RAOB is compared to 4 ACARS flights here. The ACARS go off in thesame direction as theRAOB except for one (blue). Note that forall the ACARS thetemperature is warmer than the RAOB.

Weather overview/29 Oct 2007 at 0000 UTC: Low in the Gulf of Alaska

Comparison with 0000 UTC 29 October 2007 AKN (King Salmon) RAOB.

Here is a case where TAMDAR soundingshelp correct the lower levels of the RAOB.

Comparison with 0000 UTC 29 October 2007 ANC RAOB.

The TAMDARs arein good agreementand nicely capture the lower level inversion as well as the dry layer just above the surface.

Comparison with 0000 UTC 29 October 2007 ANC RAOB.

The 0234z TAMDAR does notlook as good as theflight going up.

Comparison with 0000 UTC 29 October 2007 ANC RAOB.

Both of these TAMDARs comparewell with the RAOB.

Comparison with 0000 UTC 29 October 2007 YAK (AYA on plot) RAOB.

Not totally sureabout this comparisonbut think it is valid.

Weather overview: conditions at 0000 UTC 30 October 2007. Deep low in Gulf of Alaska

Weather overview: conditions at 0000 UTC 30 October 2007

Weather overview: conditions at 0000 UTC 30 October 2007

Comparison with 0000 UTC 30 October 2007 ANC RAOB.

There is quite a lot ofvariation in the TAMDARs for this comparison.Next we willlook more at someof these individually.

Comparison with 0000 UTC 30 October 2007 ANC RAOB.

The 2202 UTCTAMDAR compareswell with the RAOB, but theone at 0142 UTC iswarmer aloft.

Comparison with 0000 UTC 30 October 2007 ANC RAOB.

The wind thoughnear 700 mb in the 2202z TAMDARis stronger than what was found in the RAOB. Not sure which is correct.

Comparison with 0000 UTC 30 October 2007 ANC RAOB.

The 0142z TAMDAR also hasthis wind max, but even over a deeperlayer. It is warmerthan the RAOB, butIF the se strongerwinds are real thenmaybe so are the warmer temps?

Comparison of AMDARs with 0000 UTC 30 October 2007 ANC RAOB. This is just a check on

variation amongAMDAR flights. They are all in the same direction heading to the east(the RAOB tho goeswest then north).Most are warmer than the RAOB.

Comparison of AMDARs with 0000 UTC 30 October 2007 ANC RAOB.

Likewise with this set of AMDARs.

Weather overview: conditions at 0000 UTC 31 October 2007. Surface low right over Anchorage.

Weather overview: conditions at 0000 UTC 31 October 2007

Comparison with 0000 UTC 31 October 2007 ANC RAOB.

There is variation inthis very dynamicsituation. Probablythis is all real.

Comparison with 0000 UTC 31 October 2007 ANC RAOB.

Same with this set.

Weather overview: conditions at 0000 UTC 2 December 2007 – settled conditions with big ridge

Weather overview: conditions at 1200 UTC 2 December 2007 – settled conditions with big high-amplitude ridge extending over Alaska

Weather overview: conditions at 0000 UTC 3 December 2007 – settled conditions with big ridge

Comparison with 0000 UTC 3 December 2007 ANC RAOB. Some differences, but

TAMDAR soundingsshow subsidence drying and warming.

Comparison with 0000 UTC 3 December 2007 ANC RAOB.

Not sure what to make of the differences in the 2243z and 2249zTAMDARs vs. theRAOB.

Comparison with 0000 UTC 3 December 2007 ANC RAOB.

The AMDAR soundings supportthe TAMDAR temperature profileover the RAOB...interesting!

Comparison with 0000 UTC 3 December 2007 CDB (Cold Bay) RAOB. There is excellent

agreement with theCDB RAOB.

Comparison of TAMDAR flights into Dutch Harbor (DUT) with the 0000 UTC 3 December 2007 CDB RAOB to the east.

TAMDAR is not colocated with the RAOB but still a good comparison.

Comparison of two TAMDAR flights into and out of Prudhoe Bay

Comparison of Prudhoe Bay TAMDARs with 0000 UTC 3 December 2007 BRW RAOB (located to the nw).

TAMDAR and RAOB not colocated.The winds are quitedifferent. I don't think the TAMDARwinds make sensehere.

Summary

• summary of the cases is at the beginning...