\doc

TITLE. Air temperature and solar radiation data for Saddle data logger (DP211), 1990 - 2006.

ABSTRACT. Climatological data were collected from a Niwot Ridge climate station (Saddle) throughout the year using an Omnidata DP211 datapod. This instrument has a sample interval of 5 minutes and records averages of those 5-minute readings every 2 hours.  Thus, daily totals represent totals of 288 values. Parameters measured were air temperature (averages) and solar radiation (totals).

INVESTIGATOR. Mark Losleben, Tree-Ring Lab, University of Arizona, 1215 E. Lowell Street, Box 210045, Tucson, AZ 85721, losleben@email.arizona.edu.
Contact: Jennifer Morse, INSTAAR, University of Colorado, 4001 Discovery Dr., UCB 450, Boulder, CO 80303-0450, jennifer.f.morse@colorado.edu.

VARIABLES. maximum air temperature, minimum air temperature, average air temperature, total solar radiation.

KEYWORDS. climate, weather, meteorology, air temperature, solar radiation, climatology, saddle, data logger, DP211, sensor data, Niwot Ridge LTER, NWT, long term

LOCATION. Study site was the Saddle on Niwot Ridge. Collections and original data are stored at the Mountain Research Station.

TIMING. begin 15 May 1990, end 19 March 2006, daily.

CITATIONS.

METHODS. Maximum and minimum temperatures are NOT instantaneous maximum andminimum temperatures --- they are the maximum and minimum values of the2-hour temperature averages. Thus they would be expected to be less extreme than the actual maximum and minimum temperatures. Daily values were NOT calculated for days for which one or more of the 2-hour measurements were not recorded. Typically, such was the case on days during which the datapod was changed. In these cases, the hourly records might be of benefit to researchers and can be consulted --- they can be found in /data1/Datman/Climdata/Dp211/Archive on the NWT server and are of the format ddmmmyy.sdl.hr (where the date is the final date in the file). Mark Losleben provided the following regarding autumn 1994 temperature calibrations in an email message on 1 November 1994. The columns are date (mm/dd/yy), temperature as measured by a field thermometer (degrees Celsius), temperature as measured by the DP211 (degrees Celsius), and difference between the field thermometer and DP211 readings.
09/16/94,4.2,4,0.2
09/16/94,7,6,1
09/20/94,4.8,4,0.8
09/21/94,0.7,-0.5,1.2
09/22/94,-4,-5.5,1.5
09/22/94,2,1.5,0.5
09/23/94,5.9,5.5,0.4
09/23/94,9.2,9.5,-0.3
09/24/94,8.7,7.5,1.2
Thus, the value in the last column, when added to the CR21X reading, could be used to generate the "true" temperature. The mean difference between the field thermometer and DP211 based on these readings was 0.72. Note that the field thermometer had been used as a proxy for a Brooklyn standard reference thermometer accurate readable to 0.1 (degrees Celsius), based on identical readings of those 2 instruments on 15 and 29 August 1994.
Mark Losleben provided the following comments regarding temperature differences as measured by various instruments during calibration. These comments were included in a 2 December 1994 email message: "The fall 1994 calibration results were provided to become a part of the data record. No adjustment of the actual data was intended because . . . there is no consistent bias. . . . Reasons for different readings on different days are many, (and many are probably unknown). . . . the different sensors have different response times to changing conditions. Also, because they are made of different materials, they can respond differently to weather conditions other than temperature. An example might be relative humidity. Different materials condense at different rates due to inherent thermal lags. If one sensor is wetter than another, its reading is lower, assuming relative humidity is less than 100%. Another possibility is thermal eddies which are influenced by air currents and solar radiation. Also, because nothing can be measured simultaneously in exactly the sample place, two sensors do not measure exactly the same environment."
During the process of creating a "universal" tool for processing and documenting copies of raw electronic data, Mike Sannes questioned the fact that daily DP211 records had been generated from the 12 records for a given date from 0000-hr to 2200-hr. Because the hour refers to the time when the data were recorded, the 0000-hr record for a given day was actually a summary of the data for the previous 2-hr period, i.e., for the last 2 hours of the previous day. Discussion with the climatologist verified this. Consequently, the daily data files in /data1/Datman/Climdata/Dp211/Archive were deleted and the hourly data files in that directory were used to generate new daily files. The appropriate scripts were modified to assure that future daily files were generated in the proper manner. 
Metadata for saddle climatological data from other sources can be found in the files:
http://niwot.colorado.edu/meta_data/sdlcr23x-cr1000.daily.ml.meta.txt
http://niwot.colorado.edu/meta_data/sdlcr23x-cr1000.hourly.ml.meta.txt
http://niwot.colorado.edu/meta_data/sdlcr21x.daily.ml.meta.txt
http://niwot.colorado.edu/meta_data/sdltdayv.ml.meta.txt
http://niwot.colorado.edu/meta_data/sdlmtape.ml.meta.txt
http://niwot.colorado.edu/meta_data/sdlpdayv.ml.meta.txt
http://niwot.colorado.edu/meta_data/sdlrepor.ml.meta.txt
Data are missing for 1/14/2002-4/07/2002 due to DP211 wiring failure during eprom change.

\type

statistical

\header

COL1. label=date, type=string, units=none, missing value indicator=NaN, minimum=1990-05-15, maximum=2006-03-19, precision=1, definition=date (yyyy-mm-dd)

COL2. label=year, type=integer, units=none, missing value indicator=NaN, minimum=1990, maximum=2006, precision=l, definition=year

COL3. label=jday, type=integer, units=none, missing value indicator=NaN, minimum=0, maximum=366, precision=, definition=Julian day

COL4. label=airtemp_max, type=real, units=celsius, missing value indicator=NaN, minimum=, maximum=, precision=, definition=maximum air temperature

COL5. label=airtemp_min, type=real, units=celsius, missing value indicator=NaN, minimum=, maximum=, precision=, definition=minimum air temperature

COL6. label=airtemp_avg, type=real, units=celsius, missing value indicator=NaN, minimum=, maximum=, precision=, definition=average air temperature

COL7. label=solrad_tot, type=real, units=megajoulePerMeterSquared, missing value indicator=NaN, minimum=, maximum=, precision=, definition=total solar radiation

\data

http://niwot.colorado.edu/data_csvs/sdldp211.ml.data.csv

\log

The documentation section of this file was developed from the NWT LTER Data Directory (Symphony files DDABSTRA.WR1, DDDOCUME.WR1, DDMASTER.WR1, DDVARIAB.WR1; last updated 16 December 1991) by Susan Kindig and Rick Ingersoll in mid-February 1993. On 11 March 1993 data were added from daily DP211 datapod files for the period from 15 May 1990 through 26 January 1993. These files had been processed on niwotlter and quality checked by Mark Losleben in late 1992 and early 1993. See "Log of Modifications Made to DP211 Datapod Files" for additional information. Lines, dates, and missing value indicators were added for periods of missing data at this time.[RCI 11 March 1993] This file was put under sccs control on 30 March 1993. See the appropriate history file for additional log information. [RCI 30 March 1993] Data for 27 January - 15 April 1993 were appended on 7 May 1993 after being processed on niwotlter and quality-checked by Mark Losleben.[RCI 7 May 1993] Data for 16 April - 12 May were appended on 24 May 1993 after being processed on niwotlter and quality-checked by Connie Woodhouse.[RCI 24 May 1993] Data for 14 May - 26 July 1993 were appended on 25 August 1993 after being processed on niwotlter and quality-checked by Mark Losleben.[RCI 25 August 1993] Data for 27 July - 3 October 1993 were appended to the data section on 10 November 1993 after being processed on niwotlter and quality-checked by Mark Losleben.[RCI 10 November 1993] Data for 4 October - 17 December 1993 were appended to the data section on 5 January 1994 after being processed on niwotlter and quality- checked by Mark Losleben.[RCI 5 January 1994] The data section was converted to a comma delimited (as opposed to whitespace) one in order to be more consistent with other climate data files.[RCI 22 February 1994] Data for 18 December 1993 - 20 February 1994 were appended to the data section on 15 March 1994 after being processed on niwotlter and quality- checked by Mark Losleben.[RCI 15 March 199] Data for 21 February - 16 April 1994 were appended to the data section after being processed on niwotlter and quality-checked by Mark Losleben.[RCI 29 April 1994] Data for 17 April - 5 July 1994 were appended to the data section on 11 August 1994 after being quality checked by Mark Losleben.[RCI 11 August 1994] Data for the period 6 July - 22 September 1994 were appended to the data section on 7 October 1994 after being quality checked by Mark Losleben.[RCI 7 October 1994] Results of temperature calibrations done in September 1994 were added to the documentation section on 15 December 1994.[RCI 15 December 1994] Data for the period 15 May 1990 through 22 September 1994 were deleted from the data section on 13 January 1995 because of an error in the way the original daily data had been generated. See note in comments section for further explanation. Correctly generated daily data for the period 15 May 1990 through 11 December 1994 were appended to the data section on 13 January 1995. [RCI 13 January 1995] Data for the period 12 December 1994 - 26 February 1995 were appended to the data section on 4 April 1995. [RCI 4 April 1995] Data for the period 27 February through 11 May 1995 were appended to the data section on 23 May 1995.[RCI 23 May 1995] Data for the period 12 May 1995 through 23 July 1995 were appended to the data section on 8 August 1995.[MAH 8 August 1995] Data for the period 24 July 1995 through 10 October 1995 were appended to the data section on 31 October 1995.[MAH 31 October 1995] Data for the period 11 October 1995 through 22 December 1995 were appended to the data section on 6 March 1996.[MAH 6 March 1996] Data for the period 23 December 1995 through 10 March 1996 were appended to the data section on 10 March 1996.[MAH 10 March 1996] Data for the period 11 March 1996 through 2 June 1996 were appended to the data section on 12 June 1996.[MAH 12 June 1996] Data for the period 3 June 1996 through 11 August 1996 were appended to the data section on 15 October 1996.[MAH 15 October 1996] Data for the period 12 August through 13 October 1996 were appended to the data section on 18 October 1996.[MAH 18 October 1996] Data for the period 14 October 1996 through 8 June 1997 were appended to the data section on 30 July 1997.[MAH 30 July 1997] Data for the period 9 June 1997 through 28 August 1997 were appended to the data section on 30 September 1997.[MAH 30 September 1997] Data for the period 29 August 1997 through 13 November 1997 were appended to the data section on 9 December 1997.[MAH 9 December 1997] Data for the period 14 November 1997 through 9 July 2000 were appended to the data section on 27 September 2000. URL locations for related data sets were updated at that time as well.[MAH 27 September 2000] Data for the period 10 July 2000 through 26 September 2000 were appended to the data section on 16 February 2001.[TMA 16 February 2001] Data for the period 27 September 2000 to 16 May 2001 were appended to the data section on 25 June 2001.[TMA 25 June 2001] Data for the period 17 May 2001 through 21 October 2001 were appended to the data section  on 31 October 2001.[TMA 31 October 2001] Data for the period 22 October 2001 through 19 September were appended to the data section on 7 November 2002.[TMA 7 November 2002] Data for the period 20 September through 08 December 2002 were appended to the data section on 25 March 2003.[TMA 25 March 2003] Data for the period 09 December 2002 through 22 November 2003 were appended.[TMA 15 June 2004] Data for the period 23 November 2003 through 18 November 2004 were appended to the data section.[TMA 23 March 2005] Data for the period 19 November 2004 through 20 July 2005 were appended to the data section.  Blank data filler was added for the dates 14 January 2002 through 7 April 2002 where a wiring failure occured.[TMA 25 August 2005] Data for 22 July through 11 October 2005 were appended to the data section.[TMA 27 December 2005] Data for 13 October 2005 through 19 March 2006 were appended to the data section.[TMA 07 June 2006] The title was edited, labels were shortened and definitions added. [HCH 20 October 2015] Temperature units changed to celsius.[HCH 27 April 2017]