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Feature article

Access to Pacific Islands Meteorological Data in the New Zealand National Climate Database

Errol Lewthwaite and Jim Salinger (NIWA)

The National Climate Database is an archive of climate data from New Zealand, the Pacific Islands and Antarctica administered by NIWA. The database contains about 400 million data rows from about 6500 climate stations with some (New Zealand) data going back to the 1850’s. The database is classed as a "National" database by the NZ Government for recording long term measurements of climate data and is funded by the New Zealand Government’s Foundation for Research, Science and Technology. CliFlo (see below) provides free web access to the database.

Data from about 200 climate stations are loaded into the database every day and data from about 50 New Zealand stations are loaded every hour. The two main daily updated data sources are NIWA EWS (Electronic Weather Stations) and Meteorological Service of NZ (MetService) AWS (Automatic Weather Stations). NIWA EWS climate stations also record data every ten minutes. There are many manual climate stations (some rainfall only) with data received at the end of the month. Most Pacific Island data come in through MetService as "synop" data. Quality control processes identify and flag possible bad data. This is important as quality controlled observations are essential for many applications including the measurement of climate change.

Most climate parameters are recorded in the database such as temperature, rainfall, wind, solar radiation, sunshine, pressure, soil moisture, earth temperature and upper air data. Over 80 different types of monthly statistics are calculated from the base data at the end of each month.

Every climate station has a set of descriptive data recorded about it in the database. This includes basic information such as the station name, position, height, observing organisation, start and end dates, instrument types, station history (changes and problems). This information can be very important when comparing data from different climate stations. There are many gaps in this descriptive data especially for Pacific Island stations. NIWA has an ongoing project funded by SOPAC to update these descriptive data records from paper records and to digitise daily data.

The climate database contains data from over 700 Pacific Island stations including Cook Islands,Fiji, French Polynesia, Kiribati, New Caledonia, Niue, Samoa, Solomon Islands, Tokelau Islands, Tonga, Tuvalu and Vanuatu. About 65 of these stations have recent data at the end of November 2008 mostly from synops. Pacific Island countries are welcome to place more of their data into this database.

One of the oldest Pacific Island climate stations is "Samoa, Apia" (J76200). This climate station was opened in 1890 by German meteorologists at Sogi (exact location unknown) then in 1902 the Apia Geophysical Observatory was established at Mulinu’u Point by the Royal Society of Sciences, Gottingen, Germany. Measurements of total monthly rainfall, monthly mean maximum and minimum temperatures are 95% complete over this period. Interested readers can view a summarized history of this station at . http://cliflo. niwa.co.nz/pls/niwp/wstn.sensor_his?cagent=6044.

CliFlo provides free web access to the Climate Database however with some data restrictions. Users are required to subscribe on-line using the "Subscribe On-line" link on the CliFlo home page. Subscribing includes choosing a username, entering subscription details (such as name and address), describing a "Purpose" for using the data (for our statistics) and agreeing to NIWA’s Terms and Conditions of use. CliFlo users then have access to non-restricted New Zealand data. The descriptive data for each station (with some restrictions for privacy reasons) are available through CliFlo.

All Pacific Island data in the database are restricted and are grouped by country. Before a user can be granted access to Pacific Island data the user needs to obtain permission from the Pacific Island Meteorological Service who has responsibility for the those climate stations.

CliFlo and the Climate Database is a free service available to everyone and Pacific Island users are encouraged to use it.