I've just had a mini "Eureka" moment that I wanted to share.
As I've been processing more weather data from the ISD, I've been countering more cases
for smaller locations (mostly in the US) where there are two weather stations where the
WMO numbers are the same for the first part but not for the smaller part. For example, for
Socorro New Mexico there are two files:
2014 NM_SOCORRO-MUNI-AP 723620 93040
2014 NM_SOCORRO-MUNI 723620 99999
I generally interpret these cases as where a station may be switching their
instrumentation. However, in this case the two stations seem to be reporting at
alternating times (table below shows the number of observations by month for the 4 key
climate parameters that I need):
NM_SOCORRO-MUNI-AP 723620 34.067 -106.900 1485 4 -7.0 NAM BSk
2014 dbt 464 302 151 538 697 155 0* 0* 511 710 244 0* 419
2014 dpt 462 297 148 535 696 154 0* 0* 505 710 244 0* 416
2014 cld 451 245 108* 477 646 153 0* 0* 413 652 217 0* 373
2014 wsp 464 302 151 538 697 155 0* 0* 510 710 244 0* 419
2014 all 1841 1146 558 2088 2736 617 0 0 1939 2782 949 0
NM_SOCORRO-MUNI 723620 34.022 -106.903 1485 4 -7.0 NAM BSk
2014 dbt 259 389 610 161 41* 549 689 698 224 0* 444 684 431
2014 dpt 256 385 607 159 38* 545 687 698 224 0* 443 684 429
2014 cld 259 312 550 144 41* 549 598 583 182 0* 435 625 388
2014 wsp 259 389 610 161 41* 549 689 698 224 0* 444 683 431
2014 all 1033 1475 2377 625 161 2192 2663 2677 854 0 1766 2676
I have software to merge data from two files but only at defined switchover dates, so this
situation seemed at first quite hard to tackle.
Then, I thought, why not just take concatenate the two raw data files, and then sort the
combined file to get the data in the right
chronological order? That took me just a few seconds, and voila' , out comes a full
weather file with quite high data completeness:
NM_SOCORRO-MUNI-AP2 723620 34.067 -106.900 1485 4 -7.0 NAM BSk
2014 dbt 713 643 714 690 710 690 689 698 688 710 687 691 693
2014 dpt 713 643 714 690 710 690 687 698 688 710 687 690 693
2014 cld 700 531 635 613 671 688 598 583 565 652 651 625 626
2014 wsp 713 643 714 690 710 690 689 698 687 710 687 690 693
2014 all 2839 2460 2777 2683 2801 2758 2663 2677 2628 2782 2712 2696
A quick look at the plots also showed a weather file of seemingly good quality:
Problem solved!
Joe
--
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
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