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The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

1) Acceptable use. Use of the dataset will be restricted to academic, research, educational, government, recreational, or other not-for-profit professional purposes. The Data User is permitted to produce and distribute derived works from this dataset provided that they are released under the same license terms as those accompanying this Data Set. Any other uses for the Data Set or its derived products will require explicit permission from the dataset owner.
2 ) Redistribution. The data are provided for use by the Data User. The metadata and this license must accompany all copies made and be available to all users of this Data Set. The Data User will not redistribute the original Data Set beyond this collaboration sphere.
3 ) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly cite the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier. For example:

Shaver, G. 1989. Above ground biomass in acidic tussock tundra experimental site, 1989, Arctic LTER, Toolik, Alaska. Arctic LTER, Marine Biological Lab, Woods Hole, Ma 02543. 1989gsttbm http://ecosystems.mbl.edu/arc/terrest/biomass/index.shtml 

4 ) Acknowledgement. The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed significantly to its content. Acknowledgements should identify the supporting party, the party that received the support, and any identifying information such as grant numbers. For example:

Data sets were provided by the Arctic LTER. This material is based upon work supported by the National Science Foundation under Grants #DEB-981022, 9211775, 8702328; #OPP-9911278, 9911681, 9732281, 9615411, 9615563, 9615942, 9615949, 9400722, 9415411, 9318529; #BSR 9019055, 8806635, 8507493.

5 ) Notification. The Data User will notify the Data Set Contact when any derivative work or publication based on or derived from the Data Set is distributed. The Data User will provide the data contact with two reprints of any publications resulting from use of the Data Set and will provide copies, or on-line access to, any derived digital products. Notification will include an explanation of how the Data Set was used to produce the derived work.
6 ) Collaboration. The Data Set has been released in the spirit of open scientific collaboration. Data Users are thus strongly encouraged to consider consultation, collaboration and/or co-authorship with the Data Set Creator.

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While substantial efforts are made to ensure the accuracy of data and documentation contained in this Data Set, complete accuracy of data and metadata cannot be guaranteed. All data and metadata are made available "as is". The Data User holds all parties involved in the production or distribution of the Data Set harmless for damages resulting from its use or interpretation.

Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data
Dataset ID:2011-Present_MAT_HourlyWeather.01
Dataset Title:Hourly weather data from the Arctic LTER Moist Acidic Tussock Experimental plots from 2011 to present, Toolik Filed Station, North Slope, Alaska.
Investigator 1: 
First Name:Gus
Last Name:Shaver
Organization:Marine Biological Lab
Address line 2:The Ecosystem Center
Address line 3:7 MBL St
City:Woods Hole
State:MA
Zip Code:02543
Country:USA
Investigator 2: 
First Name:Jim
Last Name:Laundre
Organization:Marine Biological Lab
Address line 2:The Ecosystem Center
Address line 3:7 MBL St
City:Woods Hole
State:MA
Zip Code:02543
Country:USA
Associate Investigators:
Keywords:weather, climated, air temperature, relative humidity, radiation, wind speed, wind direction, greenhouse, shadehouse
Abstract: Hourly weather and soil temperature data from the LTER Moist AcidicTussock Experimental plots. In 1990 a Campbell CR21x data logger was installed in block 2 of the Toolik LTER experimental moist acidic tussock plots. The plots are located on a hillside near Toolik Lake (68 38' N, 149 36'W). Sensors were placed in control, fertilized, greenhouse, greenhouse fertilized, shade house and shade house fertilized sites.
For questions about the Metadata and data contact the Investigators.
For information about this web site contact:
Arctic LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7496
Email: arc_im@mbl.edu
Online URL: http://ecosystems.mbl.edu/ARC/
DATA FILE INFORMATION:
Data File URL http://metacat.lternet.edu/das/dataAccessServlet?docid=knb-lter-arc.10405&urlTail=weather/tu/data/2011-Present_MAT_HourlyWeather.csv
Data File Name 2011-Present_MAT_HourlyWeather
Beginning Date 1/1/2011
End Date 12/31/2011
Number of Data Records 8761
Other Files to Reference
Availability Status
Quality Control Information
Maintenance Description
Log of Changes: November 2013: Entered metadata into worksheet, updated columns to reflect past years.
 
RESEARCH LOCATION:                  
Location Name LTER Moist Acidic Tussock Tundra Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One  
Geographic Description Moist Acidic Tussock Tundra (MAT) Northeast corner block 1 Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description  
Location Bounding Box                  
West Bounding Coordinate                  
East Bounding Coordinate                  
North Bounding Coordinate                  
South Bounding Coordinate                  
OR if single point location                  
Latitude 68.624411 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Longitude -149.609589 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Elevation 750 In Meters In Meters In Meters In Meters In Meters In Meters In Meters  
Link to Google Map View on Google Map                
                   
 
TAXONOMIC COVERAGE:
Organisms studied
 
Methods: In 1990 a data loger and sensors were installed at block 2 of the Moist Acidic Tundra (MAT) site at Toolik Field Station Long Term Ecological Research Site (LTER). These have been used since to moniotor weather and soil temperatures. Please see temperature soil files for soil temperature information information.
Climatic conditions were measured in plots covered by green houses, shade coverage and control non-disturbed plots.
For sensor and column labels CT = Control, GH = Greenhouse and SH = shade house. Note that shade cloth and plastic greehouse material are attached to a permenant frame structure every spring (early to mid June) and removed in late August each year. Thus temperature measurements in the control plot may be representative of all three sites when the covers are not present.

Sensors in the control plot include: global solar radiation, photosynthetic active radiation, unfrozen precipitation, air temperature, relative humidity, wind speed, and wind direction at 3 meters. Additional seasons in greenhouses and shade houses plots measure air temperature, relative humidity and photosynthetic active radiation during the growing season. These sensors are read every minute and averaged or totaled every hour.

Hourly and daily summaries are in files yyyy-yyyy_SiteCode_WeatherHourly and yyyy-yyyy_SiteCode_WeatherDaily respectively, where yy is the year in which the data are collected. The original data is archived at The Marine Biological Lab, Woods Hole, MA.

NOTES:
-IMPORTANT NOTE REGARDING WINTER and LATE FALL/EARLY SPRING: Instruments are NOT maintained from Mid August (actual date varies by year) to Mid June (date also varies by year). SENSORS MAY BE COVERED WITH SNOW and/or FROZEN. Blatently erroneous has been removed however all data from winter months must be used with caution.
-The covers on greenhouses and shade houses are removed every fall and reinstalled every spring as described above.
-Only unfrozen precipitation is reported.
-Soil temperatures are problematic since frost heaving of the probes caused depth of measurements to change.
-For the global solar radiation and photosynthetic active radiation sensors no attempt is made to correct for frost or snow on the sensors during the winter months. Therefore winter radiation data should be view as suspect and used only qualitatively.

CALCULATIONS:
DAYS: JULIAN + (HOUR/2400)
VAPOR PRESS :

If Air Temp > 0 then (RH 5M/100) * 6.1121 * exp(17.368 * AIR TEMP 5M/(238.88 + AIR TEMP 5M))


If Air Temp < 0 then (RH 5M/100) * 6.1121 * exp(17.966 * AIR TEMP 5M/(238.88 + AIR TEMP 5M))
PYR TOTAL CM2 HOUR: PYRANOMETER * 0.3600 jcm2 * 1000 Watt/Kwatt
GQUANT E m2 Average (north and south quantum sensors) *60 sec *60 min * 10^-6 E/uE
GQUANT E m2 Average (north and south quantum sensors) *60 sec *60 min * 10^-6 E/uE
GQUANT E m2 Control quantum sensor *60 sec *60 min * 10^-6 E/uE


NOTE: Control PAR (CQUANT )sensor reads - 50 when in the dark.

Sensor errors, erronous data and values outside the instument rance are indicated by #N/A. Due to changes in sensor locations over time '.' have been added in years where sensors were not present. Prior to 1995 some sensors had duplicates where one was placed in the north end of the plot (indicated by N) and the other in the South (S). From 1995 onward these were replaced with a single sensor in the center of the plot. The columns for N & S were continued in later years despite no data to ease with analysis if multiple years were to be compared.

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Sensor Description

Following are brief descriptions of the sensors used at the weather monitoring station. Included with each description is a list of stations using the sensor and the number of sensors at that site. Company addresses follow the list.
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PYRANOMETER:
Li-Cor, Pyranometer: Model LI-200SA- Sensor measures global solar radiation (sun plus sky). Specs: Sensitivity - 80mA per 1000 Watts m-2. Absolute error max 5% but typically 3
QUANTUM:
Li-Cor, Quantum. Model LI-190SB. Quantum measure photosynthetically active radiation (PAR) in mmol s-1 m-2. Specs: range 400-700nm wavelength. Sensitivity 8mA/1000 mmol s-1 m-2. Relative error less then 10% for plant canopies or less then 5% for growth chambers. Toolik.
RELATIVE HUMIDITY/TEMPERATURE:
Campbell Scientific, CS500 Temperature and Relative Humidity Probe. Uses PRT for temperature measurement; capacitive RH chip for RH. Accuracy is 3% over 10-90% RH; 6% over 90-100% RH. Manufactured by Vaisala, Inc.
WIND DIRECTION:
MET-ONE, (supplied by Campbell Scientific) Wind direction use a light weight, air foil vane and a potentiometer to produce an output that varies proportional with wind direction. Specs: Minimum Wind speed to get accurate reading = 1.0 mph. Accuracy 5 Temperature range -50 to 70C.
WIND SPEED:
MET-ONE, (supplied by Campbell Scientific) Wind speed sensor Model 014A. Sensor uses a 3-cup anemometer assembly and simple magnet-read switch assembly to produce a series of contact closures whose frequency is proportional to wind speed. Specs: Operating Range - 0 to 125 mph or 0-60 m/s. Accuracy 1.5% or 0.25 mph. Working temperature range - -50 to 85C
RAIN GAUGE:
Texas Electronics, Inc. (supplied by Campbell Scientific) Tipping Bucket Electric Rain Gauge. A complex spun collector funnel with a knife edge that diverts the water to a tipping bucket mechanism. For each tip a magnet causes an electronic pulse that is recorded. Each alternate tip occurs for each 0.01 inch of rainfall. Specs: Accuracy 1% at 2 inches/hr or less. Accurate Temperature Range: 0 - 37C. Alter wind shield installed around gauge.
THERMOCOUPLES:
Omega Engineering, Copper-Constantan wire. Range -200 to 350 C. Limits of error: Standard wire 1.0C or 0.75% above 0C and 1.0C or 1.5% below 0C. Special wire 0.5C or 0.4%.
List of manufactories and suppliers.
Campbell Scientific, Inc.
81 W. 1800 N.
Logan, Utah 84321-1784
(435)750-1739

Li-Cor : 4421 Superior St, P.O. Box 4425, Lincoln, Nebraska 68504 (800)447-3576

Omega Engineering, Inc. P.O. Box 4047, Stamford, CT 06907-0047 (800)826-6342

Reference Citations: Buck, A.L. 1981 New equations for computing vapor pressure and enhancement factor. Journal of Applied Meteorology 20:1527-1532.

Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
YEAR Year datetime   yyyy    
DATE Date datetime   dd-mmm-yyyy hh:mm    
MONTH Month in integer form datetime   mm    
DAYS Julian day plus fraction of day number number     .=value missing or error
ID The datalogger program output step number number number     .=value missing or error
JULIAN Julian date number number     .=value missing or error
HOUR Time - Alaska standard time 2400 format number number     .=value missing or error
RAIN Rainfall number millimeter     .=value missing or error
GTEMP Average temperature in greenhouse - after 1994 this is a single measurement from one sensor in the center of the greenhouse number celsius     .=value missing or error
STEMP Average temperature in the shade house - After 1994 this is a single measurement from one sensor in the center of the shade house number celsius     .=value missing or error
CTEMP Temperature at 3 m height in the control plot number celsius     .=value missing or error
GRH Average relative humidity in the greenhouse - note that after 1994 this is a single measurement taken from the middle of the greenhouse number percent     .=value missing or error
SHRH Average relative humidity in the shadehousee - note that after 1994 this is a single measurement taken from the middle of the shadehousee number percent     .=value missing or error
CRH Relative humidity in the control plot at 3 m height number percent     .=value missing or error
GQUANT Green house Average Photosynthetic Active Radiation (PAR) over an hour as measured with a LiCor Quantum sensor number micromolePerMeterSquaredPerSecond     .=value missing or error
SQUANT Shade house Average Photosynthetic Active Radiation (PAR) over an hour as measured with a LiCor Quantum sensor number micromolePerMeterSquaredPerSecond     .=value missing or error
CQUANT Control Average Photosynthetic Active Radiation (PAR) over an hour as measured with a LiCor Quantum sensor number micromolePerMeterSquaredPerSecond     .=value missing or error
PYRANOMETER global solar radiation (sun plus sky), average over measurement inveral (kw/m-2/s-1) number kilowattPerMeterSquared     .=value missing or error
NET RAD Net radiation kilowatts m-2 sec-1 number meterSquaredPerSecond     .=value missing or error
WIND SPEED Wind speed at 3 meters number meterPerSecond     .=value missing or error
WIND MAG Wind vector magnitude at 3M number meterPerSecond     .=value missing or error
WIND DIR Wind direction at 3 meters number degree     .=value missing or error
WIND DIR STD Wind vector direction standard deviation number degree     .=value missing or error
VAPOR PRESS Vapor pressure for Control temperature/relative humidity at 3 meters. Formula: If Air Temp > 0 then (CRH 3M/100) * 6.1121 * exp(17.368 * CTEMP 3M/(238.88 + CTEMP 3M)) If Air Temp < 0 then (CRH 3M/100) * 6.1121 * exp(17.966 * CTEMP 3M/(238.88 + CTEMP 3M)) (Buck 1981). number millibar     .=value missing or error
VAPOR PRESS SH Vapor pressure for Shade house temperature/relative humidity at 3 meters. Formula: If Air Temp > 0 then (CRH 3M/100) * 6.1121 * exp(17.368 * CTEMP 3M/(238.88 + CTEMP 3M)) If Air Temp < 0 then (CRH 3M/100) * 6.1121 * exp(17.966 * CTEMP 3M/(238.88 + CTEMP 3M)) (Buck 1981). number millibar     .=value missing or error
PYR TOTAL CM2 HR Total joules/cm2 over an hour (PYRANOMETER * .3600 jcm2 * 1000 watt/Kwatt) number number     .=value missing or error
WIND SECTOR Wind direction at 3 meters text       .=value missing or error
COMMENTS Additional comments text        
Please contact arc_im@mbl.edu with questions, comments, or for technical assistance regarding this web site.