A Weather (Met) station is located at each of the five study sites along the C. Hart Merriam Elevation Gradient transect. Each of these stations is located in the middle of a life zone along the north side of the San Francisco Peaks. All data will be made publicly available immediately; our goal is to provide real-time data through our website. The weather stations are fully automatic. They measure wind speed and wind direction, total solar radiation, soil temperature (2 depths), precipitation, soil water content, and relative humidity (RH). Measurements are taken every 15 seconds and an average will be collected every hour as well every 24 hours to get the maximum and minimum of most of the variables. The information is processed to obtain parameters such as Potential Evapotranspiration (mm per day) as well as heat and chill units. A water balance will be calculated for each site. All the information in the future will be collected by satellite and will be available over the Internet. The weather stations consist of the following components:

1. Soil Temperature Probe. This is a 107B thermistor temperature probe. It has an accuracy of + 0.4oC over a range of -33oC to +48oC.

2. Solar Panel. MSX 10 is a photovoltaic power source used for charging lead acid batteries that provide power to the instruments, data loggers, and data storage modules. It produces 15.1 volts and a peak power of 8.9 Watts.

3. Multiplexer enclosure. AM-ENC is used to contain the data logger, multiplexer and the battery.

4. Pyranometer. LI200S Pyranometer measures solar (i.e., short wave) radiation received from a whole hemisphere. It is suitable to measure sun plus sky radiation. It is a silicon photo diode with a spectral response from 280-2800 nm.

5. Temperature and relative humidity. The HMP35C has a capacitive relative humidity sensor and a thermistor housed in a radiation shield. The relative humidity sensor can measure between 0 and 100 % of relative humidity. The accuracy is about +2% RH form 0 to 90% RH and +3% RH form 90 to 100% RH.

6. Tipping Bucket Rain Gauge. The TE425 is a standard Weather Bureau tipping bucket rain gauge. The TE525 has a resolution (i.e., one tip capacity) of 0.1 mm of rain.

7. Wind Speed and Wind Direction. A Met One Windset at each weather station will have both an anemometer (wind speed) and vane (wind direction). The range is 0 to 49 m s-1. The wind direction is measured with a precision plastic potentiometer that can produce readings between 0 and 360 degrees.

8. The CS615 is a water content reflectometer that provides a measure of the volumetric water content of a porous media. Measuring the water content in the soil, we will calculate the water balance of the site.

9. Data logger. A CR-10x data logger will be used to control all the sensors. It will be programmed to take readings every 15 seconds and take the average every hour and every 24 hours.

10. Tripod base stand 10 feet tall will have all sensors and solar panel.

Elevational Gradient Summary Weather Data

WARNING: This spreadsheet summarizes data collected from 2001 until 2005, because this coincides with a period of intense drought precipitation averages are unlikely to reflect long term averages.

Monthly average precipitation is likely highly skewed from long term averages since most precipitation fell in rare and localized events.

Due to technical difficulties precipitation due to snow fall may be under measured.

This data is provided "as is" and no warrantee as to accuracy is expressed or implied