Where is the station located?
The weather station is located on East campus. It is on top of the six story building. The station is next to the web cam for CU. click here to see the web cam.
Latitude: 40° 01' 33'' N
Longitude: 105° 25' 19'' W
Elevation: 5390 feet
What information does the station gather?
The weather station gathers:
| Gage: | Accuracy: |
| Temperature in deg C and F | ± 0.8deg C |
| Relative Humidity in percent | ± 3% typical, in natural day light ±5% |
| Solar radiation in W/m^2 | ± 3% |
| Wind Speed in m/s and mph | ±.25mph (±.11m/s) when <22.7 mph (10.1m/s) |
| Wind Direction in degrees | ±4 deg |
| Precipitation in millimeters and inches | 1 tip=0.01in. ± 1% at 2in per hour or less |
| Temperature, Relative Humidity, Battery voltage of inside the station | |
| Wind Chill | Wind Chill Units for Wind Chill (temperature): °C, °F, K Wind chill is the perceived temperature as influenced by wind speed. For example, an air temperature of 40 degrees F may seem much colder if the wind is blowing. Choose the input location and units used for the actual air temperature and wind speed measurements. The formula used in this calculation is the new (winter of 2001/2002) National Weather Service formula and may be found at http://www.srh.noaa.gov/ftproot/ffc/html/wci.shtml: or here: http://www.nws.noaa.gov/om/windchill/index.shtml Twc = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16) where: Twc = Wind Chill (°F) Wind chill is only defined for air temperature < 50°F and
wind speed > 3 mph, therefore, the program will set the wind
chill temperature equal to the current air temperature if air temperature
> 50°F or wind speed < 3 mph. |
| Heat index | Heat Index Units for Heat Index (temperature): °C, °F, K The Heat Index is the perceived temperature as influenced by the relative humidity. For example, an air temperature of 90°F would feel like 132°F if the RH was 100%. Choose whether the air temperature measurement is in °F or °C. Also choose whether you want the Heat Index expressed in °F or °C. The equation used in this calculation is from the National Weather Service; a good explanation may be found at http://www.srh.noaa.gov/bmx/tables/heat_index.html The equation is only useful if air temperature > 80°F (27°C) and relative humidity > 40%, therefore, the program will set the heat index temperature equal to the current air temperature if air temperature is < 80°F (27°C) or relative humidity < 40% or the heat index < current air temperature. The equation is: HI = heat index in °F Campbell Scientific also has a "Heat Index" Application
Note at
|
Dew Point |
Dew Point Units for Dew Point (temperature): °C, °F, K Air temperature and relative humidity (%) measurements are required for this calculation. Therefore, air temperature and relative humidity (%) sensors must be selected and configured before selecting and configuring this calculation. The equation used to calculate dew point is: Td=(241.88*ln(Vp/0.61078))/(17.558-ln(Vp/0.61078)) where Td = dew point (Deg C) The equation is an inverse of a version of Teten's equation (Tetens, O. 1930. Z. Geophys., 6:297), optimized for dew points in the range -35 to 50°C, and is accurate to within ±0.1°C within that range. Vapor pressure is calculated by the datalogger with the following equation: Vp=RH*SVp/100 where RH = relative humidity (%) Saturation vapor pressure is calculated by the datalogger with the following approximating polynomial (see Lowe, P.R. 1930. J. Appl. Meteor., 16:100-103): SVp=6.107799961+T*(4.436518521*10^-1+T*(1.428945805*10^-2+T*(2.650648471*10^-4+T*(3.031240396*10^-6+T*(2.034080948*10^-8+6.136820929*10^-11*T))))) where T = air temperature (dry-bulb temperature) (°C) Some datalogger models have built in instructions for calculating Vp and SVp using the above equations (e.g. CRBasic DewPoint instruction and Edlog P56 instruction), others do not and will include the complete equations in the resulting datalogger program. |
A pic of inside the station: CR10X is behind the black COMM 220 modem. The blue ribbon connects from the CR10X to the modem, which then sends the data through the phone line to the computer.
How often does the station gather data?
The weather station gathers data every 2 seconds and then sends the average directly to the web site. The station also takes records for every thirty minutes. It takes the average wind speed, the maximum wind speed, average temperature, average relative humidity, and the total precipitation with in the thirty minutes.
Weather Station
The weather station is an ET
106 made by Campbell Scientific. Click here to go to Campbell
Scientific website. The data is taken by the weather station and then
sent through a phone line, which is connected to a phone modem in a computer.
Then the data logger (Logger Net 3.4.1) collects the data and RTMC Pro
3.0 illustrates the data onto a graph. Finally, it is displayed on the
internet through RTMC Web Server.
A view looking northwest
Here are some unique weather patterns for the Rocky Mountain Foothills
Mountain and Valley Breeze.
The Red Dots illustrated the wind direction (deg), and the green squares on the bottom graph illustrate the Wind Speeds (mph).
90 Degrees (East Wind-Valley Breeze) during the day
270 Degrees (West Wind-Mountain Breeze) at night.
We see these wind shifts because of the difference of surface heating.
During the day the valley becomes warmer than the Mountain areas, thus
the winds blow from the east because of the temperature gradient. At night,
the valley cools more quickly and we see winds develop from the warmer
mountain area (Mountain Breeze). These winds are breezes, not wind storms,
thus the wind speeds should be mild.
Cold Front
Cold Front passing at 10 pm. The Air Temperature Decreased, Relative Humidity Increased, and the Dew point increased to the air temperature. Some Precipitation even fell.
October Snow Storm
We can see the effects of the October snow storm that occurred on 29 OCT09. We can see that the wind speeds went to zero. This could be explained by the anemometer, being blocked by the snow fall that had accumulated around the instrument. The Solar Radiation decreased dramatically from the overcast skies.
Wind Storms
In the period of a month we can see that there were 3 wind events that occurred where max wind speeds were over 45 mph. We see these wind events because of Boulder's unique geographic location--in the foothills of the Rocky Mountains.
Dramatic Temperature fluxuations
Around 10 am on 3 NOV we saw a 14 deg C or a 25 deg F temperature increase in two hours. On this particular day, there was low level fog in the morning and after the cloud cover dissapated, temperatures increased dramaticly, and the relative humidity decreased as well, because of the increased amount of Solar Radiation reaching the ground. This change went from a cool moist morning to a warm dry afternoon.
Clear vs. Cloudy
On 1 NOV we can see that it was a clear day from the symmetrical parabola. Compared to 2 NOV where it was a cloudy day and the Solar Radiation was lower and variable throughout the day given the amount of cloud cover.
Contact the Geography department for any information.