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.
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
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/
Soil moisture is measured with a water content reflectometer (WCR) beginning in 1998 (PRIMET) replacing older gypsum block technology. Mean 5-minute soil temperatures are measured at the four benchmark stations (PRIMET, CENMET, UPLMET, VANMET) at four depths (10, 20, 50, 100 cm) starting in either 2014 or 2015. Since 2015, daily data is post-calculated from all 5 minute mean values for the day. Max-min values are based on 5 minute mean intervals and not instantaneous values. Prior to that, mean hourly soil temperatures were measured starting in May 2012 and mean daily soil volumetric water content was calculated on 15 second samples starting in 2001 or 2002 for the other three sites. Daily max-min values were based on instantaneous 15 second readings.
Gypsum blocks were used to record mean daily soil moisture potential at the four benchmark stations (PRIMET, CENMET, UPLMET, VANMET) beginning in 1994. Water content reflectometers were added beginning in 1998 at all sites and all gypsum block measurements were terminated by May 2000. Hourly measurements were made between 1988 and 1990 at PRIMET but were discontinued and restarted in Oct 1994 on a daily basis only. At VANMET, soil moisture potential measurements were summarized by daytime and nighttime hours only from 1987 to 1994 at depths of 10, 20, 30 cm. From 1987 to 1993, mean daily soil moisture potentials were recorded in the rooting zone of 3 individual trees at VANMET.
Mean 5-minute soil temperatures are measured at the four benchmark stations (PRIMET, CENMET, UPLMET, VANMET) at four depths (10, 20, 50, 100 cm) starting in either 2014 or 2015. Prior to that, and from the beginning of data collection, mean hourly soil temperatures were measured. Collection at the secondary benchmark site, WS7MET, began with 10-minute means at the end of 2006 and was switched to 5-minutes means with the other sites. Thermocouple wire was used in the earliest measurements and were protected inside of a PVC structure. Most measurements begin in 1994 but measurements were made at PRIMET beginning in 1988 at 20 cm depth only. At VANMET, measurements were summarized by daytime and nighttime hours only from 1987 to 1993 at depths of 10, 20, 30 cm, and soil temperature was recorded in the rooting zone of 3 individual trees.
