This is a bit of an odd project from NOAA and Cornell. A more practical name might be “spliced” but I think they just like being able to say:
“If it positively, absolutely, has to be extreme, use ThreadEx”
“SpliceEx” doesn’t sound cool.
At least they realize how surface temperature records get fractured. Of course, while the method is useful, the data representing extremes may very well be crap in some instances. The problem these guys have (and NOAA in general) is that they seem to have no idea of the conditions which contribute to the measurement extreme. They just data mine. For temperature records, UHI and microsite bias is an issue that has not been investigated on a station by station basis.
For example they thread together Baltimore’s three stations as one of the threaded records.
But as we know, Baltimore’s two most recent stations have serious temperature bias issues, as outlined here and here at WUWT. So what good are threaded records if you don’t know the quality of the extremes data?
The links section at the bottom of the article has all the data files. Visit the URL below to try out the interface. – Anthony
ThreadEx is a project designed to address the fragmentation of station information over time due to station relocations for the express purpose of calculating daily extremes of temperature and precipitation.
There are often changes in the siting of instrumentation for any given National Weather Service/Weather Bureau location over the observational history in a given city/region. As a result, obtaining a long time series (i.e., one hundred years or more) for computation of extremes is difficult, unless records from the various locations are “threaded” or put together. This has been done, but different approaches and combinations of stations have resulted in confusion among data users and the general public about what constitutes an official daily extreme record.
In consultation with NOAA’s National Climatic Data Center (NCDC) and the National Weather Service (NWS), the Northeast Regional Climate Center (NRCC) has evaluated station relocations and built “threads” for 270 locations that are published in NCDC’s Local Climatological Data using NOAA daily data sets. The data sets used for this project include NCDC DSI3210, DSI3200, DSI3206 and DSI3205. In addition, NRCC has been able to extend over sixty station threads back further in time using daily data contributed by local NWS offices, state climate offices and regional climate centers. An ongoing process of adding daily data from the old NWS Climate Record Books is also underway. These data have been digitized, passed through quality control and used to extend threads back even further in time for over fifty stations to date (see revision history for details).
Methodology for Developing Threads
The record of a currently active station was used as the starting point for a station thread. This station’s current record was used as far back in time as possible, taking precedence over a closed station’s record during any periods of overlap. A search was conducted to identify other weather stations in the area that could be used to extend the thread further back in time. In this process, preference was given to Weather Service/Bureau stations (that were not themselves LCD stations). The thread was extended back in time as far as possible using NOAA daily data available in digital form. Partner input was solicited and this local expertise was used to fine-tune the station threads.
Version 5.1 – released 26-March-2010.
h/t to WUWT reader Pamela Gray