Much of the early climatological measurements on the Andrews Forest were associated with the investigation of the initial small watersheds experiment (Watersheds 1, 2, 3). The Climatic Station on WS 2 was installed in 1956 to measure precipitation and a hygrothermograph was added in 1958. The High-15 station was established to measure precipitation in 1964 in conjunction with small watersheds 6, 7, 8, and has evolved into a secondary meteorological station. A more general set of modeling needs led to the installation of the Primary Meteorological Station in 1972 to characterize the meso-scale environment. Originally, solar radiation, air temperature, dew point temperature, and windspeed were collected. Along with precipitation from the climatic station on WS 2, these were the primary climatic variables needed for the models predicting the rates at which materials accumulate or move through ecosystems (Waring et al., 1978). Significant improvements to the station were made in 1975, 1979, and 1988, as the station evolved from chart recorders to state-of-the-art digital data loggers (Bierlmaier and McKee, 1989). The Vanilla Leaf Met Station was installed in 1987. The primary intent was to provide micro- meteorological data for a study of seedling survival following clearcut and shelterwood logging at high elevation. Ultimately, the shelterwood site was discontinued and the clearcut site has evolved as a primary high elevation meteorological station.
Four Benchmark Meteorological Stations (BMS) and two second-level stations are included in the MS001 database. The Primary Meteorological and Vanilla Leaf Meteorological BMS are retained. Two new BMS are installed. In 1994, the Upper Lookout Meteorological Station was established at high elevation (4200 ft, ENE aspect) on clearcut L708 in the SE Andrews. In 1995 the Central Meteorological BMS was established at a centrally located site on clearcut L351 (3300 ft, WSW aspect) in the east-central Andrews. A GIS analysis of elevation and aspect indicated the average elevation (3170 ft., 966 m) and average aspect (267 degrees) of the Andrews Forest, and the Central Met Station was located to represent these general averages. Modifications are made to the Primary and Vanilla Leaf Stations to standardize measured variables, temporal resolution, methods, and instrumention across all BMS. Sites will be cleared and required openings maintained following standards of the National Weather Service, the LTER network, and where appropriate, the NADP network. Telemetering of all BMS was completed in 1996. Second-level stations (SLS) at the Hi-15 and WS 2 Climatic Station will continue to be maintained for measurement of precipitation, temperature, and other data to maintain continuity of historical records. These sites also follow established procedural standards.
The BMS include meteorological measurement of air and soil temperature, relative humidity, calculated dew point temperature and vapor pressure deficit, wind speed and direction measurement, incoming solar radiation, photosynthetically active radiation (PAR), soil moisture, snow melt, and snow moisture and depth.
Please follow this link to view climate data collection methods that have been used over time at select stations. Results can be filtered by parameter, climate station, and date range. A general text search is also available.
https://hjandrews.shinyapps.io/im_methods_history/
Mean downward and upward shortwave and longwave radtion and total net radiation are recorded at two benchmark stations (PRIMET, UPLMET) using a NR01 4-componenet senor and are output every 5 minutes starting in 2013. Mean downward and upward shortwave are recorded at the secondary benchmark site, WS7MET, using pyranometers and are output every 10 minutes beginning on 2/16/2007. Output was switched to 15 minutes on 9/24/2012, then switched to 5 minute output on 4/30/2015. Daily mean downward and upward shortwave and longwave radtion and total net radiation data are post-calculated in watt per m2.
The follow link describes data collection methods (by date range and resolution) that have been used by each unique probe. Results are filtered by database code, sitecode, parameter, and probe.
https://andlter.forestry.oregonstate.edu/MethodCode/View_History.aspx
Mean Photosynthetically active radiation (PAR) is measured at Central Meteorological Station (CENMET) and output at every 5 minutes starting in April 2015. Prior to that output every 15 minutes starting in 1998. Maximum solar radiation is based on instantaneous micromoles per second per square meter, and the time of the maximum value is accurate to the minute. It is common for solar radiation sensors to read negative at night (-1 to -7), and negative nighttime readings are changed to 0. The daily values average in these negative values, creating a minor error in the daily values.
Total incoming solar radiation is recorded at the four benchmark stations (PRIMET, CENMET, UPLMET, VANMET) and output every 5 minutes starting in 2014 or 2015. Prior to that output every 15 minutes starting in 1994. Collection at the secondary benchmark site, WS7MET, began with 10-minute means at the end of 2006 and was switched to 15 minute output in 2012, then switched to 5 minute output with the other sites.This total incoming solar radiation data is also output every day in megaJoule per m2 along with the maximum daily rate of incoming solar radiation in watts per m2 and the time of the maximum accurate to the minute. Solar radiation measurement began in 1972 at PRIMET, but much of the incoming solar radiation data from the 1970's is estimated. Values are output on an hourly basis until 1994 at PRIMET. Data had originally been output as langleys but has been converted to more standard units.
A description of the early processing history and instrumentation for the Primary Meteorological Station (PRIMET), 1972-1989, is posted here:
http://andrewsforest.oregonstate.edu/data/studies/ms01/ms001_primet_1972_1989.pdf
