Air
and Soil Temperature |
Precipitation
 |
Soil Moisture
 |
Air and Soil Temperature
Description: A pilot air and soil temperature measurement program was initiated in July 2001 at the Bear Brook Watershed in Maine (BBWM). This pilot project provided the framework for a more comprehensive measurement and data analysis program of soil and air temperature at BBWM support by a National Science Foundation (NSF) Long-Term Research in Environmental Biology (LTREB) study known as LTREB: Forest Ecosystem Response to Changes in Atmospheric Chemistry and Climate at the Bear Brook Watershed in Maine (NSF award #0210257). The program was developed in an effort to determine what relationships may exist between climate, and the biogeochemical and hydrologic processes being studied at the East and West Bear Brook Watersheds. The immediate objective of this temperature study under NSF LTREB is primarily to develop the framework for the BBWM temperature data base that will be continuously updated into the future as a result of the air and soil temperature measurement program.
Instrumentation and Data Collection: Initially, through a cooperative agreement with the US Forest Service, eight HOBO H8 Outdoor/Industrial 4-channel data loggers (Onset Computer Corporation) were launched at the two watersheds in July 2001. Two data loggers were installed in the hardwood and softwood forest stands of each watershed. In June 2003 two additional data loggers were installed in the hardwood and softwood forest stands of each watershed (i.e. 4 instruments per stand). Temperature readings for each data logger are collected at 3 hour time intervals from 4 sources: air, O horizon, and at mineral soil depths of 10 and 25 cm.
Data Summary: Average monthly temperatures recorded at BBWM exhibit a sinusoidal annual pattern for all probes, with troughs occurring in the winter months and peaks in the summer months. Temperatures appear to reach a minima in January and maxima in August for each year. Minimum temperatures for mineral soils appear to linger from January until March before they start to increase, whereas maximum temperatures are reached in August and immediately decline in September for air and soil. Temperatures within the watershed exhibit expected seasonal inversion with deeper probes registering warmer temperatures in the winter compared to shallow probes or air, and cooler temperatures in the summer. The seasonal amplitude in temperature decreases from air to soil and with soil depth.
Description: A soil moisture measurement program was initiated in June 2003 to provide additional information in conjunction with the LTREB programs currently being conducted at BBWM. The program was developed in an effort to determine what relationships may exist between soil moisture and other biogeochemical and hydrologic processes being studied at the East and West Bear Brook Watersheds. The immediate objective of this study is primarily to develop a data base that will be continuously updated and available to research personel.
Instrumentation and Data Collection: A single HOBO Micro Station data logger (Onset Computer Corporation) was launched in the East Bear Brook Watershed in June 2003. Measurements of soil moisture are continually collected at 3 hour time intervals and averaged across the top 25cm of the mineral soil. Temperature is collected at a depth of 10cm of the mineral layer.
Data Summary:
Description: Precipitation at BBWM has been monitored off and on since 1985. A comprehensive and current database has been compiled using data collected since September 2002 to provide supplemental information in conjunction with other environmental data. Similar to soil moisture, the immediate objective of this effort is primarily the development of database that will be continuously updated and available to research personnel.
Instrumentation and Data Collection: Data is collected using a Belfort Universal Precipitation Gauge. The instrument is currently located on a stage above the East Bear Brook weir. The gauge collects precipitation (rain, snow, etc.) in a weighing chamber. The instrument is designed to convert the weight of any accumulating precipitation into depth equivalents (i.e. inches). The data is continually recorded by pen on a rotating chart.
Data Summary: Precipitation events appear to have occurred in an almost cyclical and consistent pattern from September 2002 until September 2003. However, from late 2003 throughout the first half of 2004 there is a noticeable decrease in the magnitude and frequency of events which might be considered by some a "dry spell". The "dry spell" appears to have ended abruptly around June 2004 where the frequency and magnitude of precipitation events increased dramatically, primarily in early 2005.
