Comments on: GHCN Updates

By: Still I look to find a reason to believe « jdwill07 blog

Still I look to find a reason to believe « jdwill07 blog — Fri, 11 Dec 2009 13:43:54 +0000

[...] temperature record is not as simple and well anchored as one might wish. There are indications that the record is incestuous and less robust than advertised (not the legions of scientists [...]

By: Internal Report Says U.N. Climate Agency Rife With Bad Practices « Watts Up With That?

Thu, 04 Dec 2008 16:05:49 +0000

[...] Bad Practices 4 12 2008 Perhaps now the problems with disappearing weather stations and slow or non-existent updates of GHCN weather data can be explained. The U.N. appears to be ineffective at managing basic science data gathering. – [...]

By: steven mosher

steven mosher — Mon, 01 Dec 2008 13:43:31 +0000

re 23. ok.

By: Len van Burgel

Len van Burgel — Mon, 01 Dec 2008 10:56:12 +0000

Re: steven mosher (#22), Steven, I don't disagree with you, but I thought it instructive to try to work out why it could be that such a long period record is rejected. If I get time, I will look at any other Australian records rejected.

By: steven mosher

steven mosher — Mon, 01 Dec 2008 08:00:04 +0000

re 21, A short record or records with lacuna would not be deleted prior to processesing as the processing has step to “overcome” these issues by combining stations within geographical areas according to the ‘reference station method’
(either Karl or Peterson et al ) this is a step0 function in gistemp I believe ( from memory… impaired memory since I have suffered through reading gistemp more than the FDA recommends)

By: Len van Burgel

Len van Burgel — Mon, 01 Dec 2008 01:00:11 +0000

Re: steven mosher (#20),

The only Australian station in your abbreviated list is Kempsey.

Kempsey (Lat -31.08 Lon 152.08) has records back to 1882 and is still open. Temperature records are available from 1907. Kempsey is also known as Kempsey (Wide Street). Another station opened at Kempsey Airport in 2001 called Kempsey Airport AWS. It is 5km to the west further inland.

The Bureau reports the daily observations as follows:
“Temperature, humidity, cloud and rainfall observations are from Kempsey (Wide Street) {station 059017}. Wind and pressure observations are from Kempsey Airport AWS {station 059007}”.

I suspect GHCN either is supplied with Kempsey Airport AWS data (or it assumes it is) and therefore because of its short record it is deleted. In addition although temperature records for Kempsey (Wide Street) go back 100 years, there are 10 years listed as missing mostly in the 1961-1990 period. That may also be a problem.

By: steven mosher

steven mosher — Sun, 30 Nov 2008 06:24:05 +0000

re 16. GISS ommission are listed in Step0 input files. See the file Ts.strange.RSU.list.IN. for some of these stations certain time periods are omitted, for others, the entire period is ommitted. There are no documents that explain or allow one to understand these ommissions. here’s a partial sample:

115624640010 HURGHADA lat,lon 27.3 33.8 omit: 0-9999
134652010000 LAGOS/IKEJA lat,lon 6.6 3.3 omit: 0-9999
134652360000 WARRI lat,lon 5.5 5.7 omit: 0-9999
134652430000 LOKOJA lat,lon 7.8 6.7 omit: 0-9999
205549450010 JUXIAN lat,lon 35.6 118.8 omit: 0-9999
207433330002 PORT BLAIR lat,lon 11.7 92.7 omit: 0-9999
210476960010 YOKOSUKA lat,lon 35.3 139.7 omit: 0-9999
219415600005 PARACHINAR lat,lon 33.9 70.1 omit: 0-9999
303824000000 FERNANDO DE N lat,lon -3.9 -32.4 omit: 0-9999
314804440000 CIUDAD BOLIVA lat,lon 8.2 -63.5 omit: 0-9999
403717300040 RUEL,ON lat,lon 47.3 -81.4 omit: 0-9999
414762200010 CIUDAD GUERRERO,CHIHUAHUA lat,lon 28.6 -107.5 omit: 0-9999
414762580020 QUIRIEGO, SONORA lat,lon 27.5 -109.2 omit: 0-9999
414763730000 TEPEHUANES,DG lat,lon 25.4 -105.7 omit: 0-9999
414766950010 CHAMPOTON, CAMPECHE lat,lon 19.4 -90.7 omit: 0-9999
414767750030 CANTON, OAXACA lat,lon 18.0 -96.3 omit: 0-9999
440785260010 ANNAS HOPE, ST.CROIX VIRG lat,lon 17.7 -66.7 omit: 0-9999
425724910030 HOLLISTER USA lat,lon 36.8 -121.4 omit: 0-9999
501947880000 KEMPSEY lat,lon -31.0 152.8 omit: 0-9999

By: steven mosher

steven mosher — Sun, 30 Nov 2008 06:07:44 +0000

re 26. DC GHCN stations are dropped from GISS for a variety of “reasons” none of which is stated very clearly. You can refer to hansen 2001 to get some feel for the QC reasons but was ignored. Most of the “cleaning” happens by hand.

One place to start is by downloading the GISTEMP code and having a look at the various readme files. also some of the input files provide some clues. If you need help holler..

By: Steve McIntyre

Steve McIntyre — Sat, 29 Nov 2008 22:56:23 +0000

My own take is that the information is probably OK in the national services. The priority is surely for them to find out why these errors occur rather than throwing another patch. If they find out why the errors occur, maybe they’d find out why the miss data that is plainly available.

These people are paid to collect this data. I just don’t believe that it’s that hard a problem.

By: Deep Climate

Deep Climate — Sat, 29 Nov 2008 22:05:12 +0000

I’ve checked 2007 GHCN monthly for “carryover” errors of the sort that plagued the initial GHCN October data. I checked all six spring and fall monthly transitions (i.e. Feb-Mar, Mar-Apr, Apr-May, Aug-Sep,Sep-Oct, Oct-Nov). All stations having at least one “0 transition” were identified and sorted by maximum absolute transition. The only definite carryover errors identified were for the two Slovakia stations. Here there was a whopping 8 degree rise from May to June, but identical temps in April and May. Comparison with nearby Czech Republic shows that this is not possible.

64111903000 48.65 19.15 SLIAC
20 26 62 106 106 190

64111934000 49.07 20.25 POPRAD/TATRY
14 2 39 83 83 166

61111782000 49.68 18.12 OSTRAVA/MOSNO
36 28 56 99 153 189

I also checked the GHCN daily for POPRAD and that also shows a large difference from April to May. There were a lot of missing days in that file.

But other possible candidates seem to be chance occurrences (lots of those in the tropics, of course). In particular, the rest of the temperate zone 0 transitions seem due to juxtaposition of warmer and colder months in a region, resulting in some chance 0 transitions. For example, consider the following stations in Luxembourg and France:

62906590000 49.62 6.22 LUXEMBOURG/
49 50 64 146 146 172
61507222000 47.17 -1.6 NANTES
84 92 84 145 145 170
61507510000 44.83 -0.7 BORDEAUX/MERI
81 97 97 156 161 189
61507280000 47.27 5.08 DIJON
53 64 69 147 156 185
61507434000 45.87 1.18 LIMOGES
56 72 71 148 139 166
61507630000 43.63 1.37 TOULOUSE/BLAG
67 85 90 152 159 198

Throughout the region, March was cool and April was warm leading to small transitions between both Feb-Mar and Apr-May. The Luxembourg daily data shows only .3 deg difference between the average mean for April and May (calculated as min-max average), tending to confirm this analysis.

By the way, the three April errors in 2008 (Resolute etc.) are still there in the latest archive. All the same, the prior incidence and impact of “carryover” appears to be quite limited, at least as far as I can see in the 2007 and 2008 data. It should still be fixed though. This may require a screening process to identify probable carryover errors, based on automation of the above procedure.