Arctic LTER Database

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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:

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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.

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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 via LTER Data Poral
Dataset ID:2012_GS_ITEX_ShrubCanopy_DailyLogger.05
Dataset Title:Daily summaries of photosynthetically active radiation (PAR), relative humidity, and temperature data logged above, within, and below Betula nana and Salix pulchra shrub canopies during the summer of 2012 in vicinity of Toolik Lake, Alaska.
Investigator 1: 
First Name:Gaius
Last Name:Shaver
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
Address line 3:
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Investigator 2: 
First Name:Edward
Last Name:Rastetter
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Investigator 3: 
First Name:Mathew
Last Name:Williams
Organization:University of Edinburgh
Address line 2:School of Geosciences
City:Edinburgh
State:
Zip Code:EH9 EJU
Country:United Kingdom
Investigator 4: 
First Name:James
Last Name:Laundre
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
Address line 3:
City:Woods Hole
Zip Code:02543
Country:United States
Investigator 5: 
First Name:Laura
Last Name:van der Pol
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Associate Investigators:
Keywords:photosynthesis, shrub canopy, relative humidity, temperature, photosynthetically active radiation
Abstract:This file contains limited daily summaries of PAR, relative humidity, and temperature data monitored above, within, and below Betula nana and Salix pulchra shrub canopies at two locations near Toolik Lake, Alaska during the summer of 2012. The location of the PAR sensor and dataloggers were co-located with the LTER shrub plots (block 1 and 2), also used for the chamber flux and point frame measurements taken this same year. There were two logging sites (block 1 and 2), each of which had PAR five PAR sensors, two for each shrub canopy and one above, as well as three sensors to log relative humidity and temperature. This file contains maximum PAR, total daily PAR, and daily average temperature data, as well as intermittant maximum and minimum values for temperature and relative humidity. Data monitored every five minutes is available in the file "ShrubCanopy_InstantLogger".
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.10143&urlTail=terrest/tracegas/data/2012_GS_ITEX_ShrubCanopy_DailyLogger.csv
Data File Name 2012_GS_ITEX_ShrubCanopy_DailyLogger
Beginning Date 6/23/2012
End Date 8/14/2012
Number of Data Records 435
Other Files to Reference 2012_GS_ITEX_BF3_DiffuseLightData; 012_GS_ITEX_CH_SoilData; 2012_GS_ITEX_CHFluxData; 2012_GS_ITEX_LC_ParameterSummary; 2012_GS_ITEX_MaxCanopyHeight; 2012_GS_ITEX_PercentCover; 2012_GS_ITEX_CHN_Data; 2012_GS_ITEX_PF_LAISummary; 2012_GS_ITEX_RawPinDrop_Data; 2012_GS_ITEX_ShootACiData; 2012_GS_ITEX_ShootHarvestData; 2012_GS_ITEX_ShrubCanopy_DailyLogger; 2012_GS_ITEX_InstantLogger; 2012_GS_ITEX_SunScan_LAI; 2012_GS_ITEX_SunScan_PAR; 2012_GS_PFandCH_GPS; 2012_GS_ITEX_PF_ShootLightCurve; 2003-2004gsfluxleafN; 2003-2009gscurveparameters; 2003-2009gsflux; 2003-2009gsGPSandveg; 2003-2009gsharvestLAI-N; 2003-2009gsspecieslist; 2004-2009gscoverft; 2004-2009gscoversp;
Availability Status 1
Quality Control Information Temperature values >30deg C were changed to "NaN"; PAR values < 0 or > 2500 were changed to "NaN"; relative humidity values <0 or >100 were converted to "NaN".
Maintenance Description This was a season-long project, though it followed similar methods to ITEX projects performed starting in 2003 that are likely to be replicated in the future for reasearch at the Toolik Field Station, AK.
Log of Changes: Version 2: Updated units to current standards. Missing values changed to #N/A. CH 28Jan2013
Version 3: Updated metadata to newer form (with sites sheet). CH April 2013.
Version 4 corrected eml exel file name JimL 16May13
Version 5: Corrected Distrubution URL. It had xlsfiles in the path. Jim L 19Jun14
 
RESEARCH LOCATION:                  
Location Name LTER Shrub Block 1 LTER Shrub Block 2 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 Upland site; co-located in Block 1 of the Shrub LTER sites; IVO 68 38'18.8" N, 149 34' 07.2" W +/- 50m. Plots are outside of the designated LTER treatments, though are exposed to the same environmental conditions. All plots were chosen by the dominant shrub canopy (either Salix pulchraor Betula nana) and preferentially selected to be 90cm+ in height. Outlet site; co-located in Block 2 of the Shrub LTER sites; IVO 68 38'008.1" N, 149 35' 017.1" W +/- 50m. Plots are outside of the designated LTER treatments, though are exposed to the same environmental conditions. All plots were chosen by the dominant shrub canopy (either Salix pulchraor Betula nana) and preferentially selected to be 90cm+ in height. 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 68.6385555555555 68.6355833333333 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Longitude -149.568666666666 -149.588083333333 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Elevation 747 m 730 m In Meters In Meters In Meters In Meters In Meters In Meters  
Link to Google Map View on Google Map View on Google Map              
                   
 
TAXONOMIC COVERAGE:
Organisms studied Betula nana; Salix pulchra
 
Methods:Automated Data Logging
In order to monitor canopy conditions of the shrub species of interest--Betula nana and Salix pulchra--two CR1000 dataloggers (Campbell Scientific, 815 W. 1800, North Logan, UT, USA) were installed at the sites used for the ITEX shrub canopy studies at Toolik Field Station in Alaska the summer of 2012. The sites (see "Group" category) are labeled as "Upland" and "Outlet"--descriptions of the sample site in relation to Toolik Lake. The Upland site is colocated with Block 1 of the LTER shrub vegetation plots; the Outlet site is colocated with Block 2. The dataloggers were adjacent to, rather than within, LTER plots.

Both the Upland and Outlet datalogger had the following sensors which logged every five minutes:
(5) Photosynthetically active radiation (PAR) sensors: LI-190SB Quantum Sensor (Li-Cor Biosciences, 4647 Superior St, Lincoln, NE, USA)
* Sensors were placed as follows: (1) Above all vegetation at a height of 2.2 meters


(1) Mid-way within the B. nana canopies (approximately 40 cm above the soil)


(1) Mid-way within the S. pulchra canopies (approximately 40 cm above the soil)


(1) Below the B. nana canopies (approximately 10 cm above the soil)


(1) Below the S. pulchra canopies (approximately 10 cm above the soil)

(3) Relative humidity (RH) and temperature sensors: HMP50/HMP60 Probe (Campbell Scientific, North Logan, UT, USA)
* Sensors each had either a 6- or 10-plate radiation shield (Campbell Scientific model 41303-5A or 41003-5)
* Sensors were placed as follows: (1) Above all vegetation at a height of 2 meters


(1) Below the B. nana canopies (approximately 10 cm above the soil)


(1) Below the S. pulchra canopies (approximately 10 cm above the soil)

These instantaneous data are available in the file "Instant_Logger". The extreme values that sensors encountered were also recorded; these are included in this file.

The temperature monitoring performed by the datalogger itself (maximum and average daily temperatures) do not represent direct air temperatures as the datalogger was housed in a sealed, white, hard-plastic box mounted approximately 1.5 meters above the ground.

SunScan LAI and PAR Measurements:
As with other measurments collected the summer 2012 for the ITEX project at Toolik Field Station, a Delta-T SunScan wand (Delta-T Devices Ltd, Burwell Cambridge, UK) was use to characterize the shrub canopies with the dataloggers. These data are included in the datasets: "SunScan_LAI_Data" and "SunScan_PAR_Data". The methods used for each are described below.

The methods used to collect PAR at many heights within each canopy were the same used to collect LAI, with the difference being the setting on the SunScan wand. The measurements were taken near the end of the growing season when leaves were already beginning to senesce. Additionally, while these measurements are traditionally made in conjunction with a Beam Fraction sensor (BF3), this sensor was malfunctioning when the datalogger sites were sampled , and thus it was not used. Instead of the BF3 sensor, wand measurements above the canopy were made immediately prior to each data measurement to record the ambiant total irradiance levels.

Readings were taken by inserting the SunScan wand near to the ground as possible--typically starting at 5 centimeters from the ground (the wand rested atop the moss layer)--and then repeated every 15 cm with the last measurement being above the canopy. Measurements were taken with the field technician opposite the direction of the sun at five locations within the canopy at each height. Five replicates were taken at each height in the canopy immediately surrounding the datalogger sensors; this differs from the ITEX samples which had three replicate scans at each height.

The weather conditions during these measurements were almost uniform cloud cover; thus nearly all of the measurements were taken under "diffuse" light conditions (diffuse light fraction greater than 0.7). The measurements taken with "direct" light conditions were taken on partly cloudy days.

The SunScan wand measures PAR along 64 points along a 1-m horizontal profile. When sampling PAR within the shrub canopy, the data are from the raw output from each PAR sensor. When sampling LAI, there is an internal calculation performed though the Delta-T software that compares the reading above the canopy to the reading within the canopy, and takes into account the percent of absorbed PAR (assumed to be 0.85), and the ellipsoidal leaf angle distribution parameter (ELADP*) (assumed to be 1.0).

In addition to the LAI values, the Delta-T SunScan instrument gives an output of other variables including: transmitted light, spread among sensors, beam fraction, and zenith angle. These values are further described here:

Transmitted Light: the fraction of incident light that passes through a given canopy. It can refer to Direct, Diffuse, or Total incident light.

Spread: the standard deviation of the 64-PAR sensors on the SunScan wand.

Beam Fraction: the fraction of the Total incident PAR in the Direct beam.

Zenith Angle: the angle between the centre of the sun and the point directly overhead.
Zenith angles are calculated from latitude, longitude, and local time using standard astronomical equations as given in Practical Astronomy. The location used to determine the local zenith angle was: 68 37' 39" N, Longitude 149 35' 51" W.

*"ELADP is a way of characterizing the horizontal or vertical tendency of leaves in a canopy." p 37 of SS1 User Manual v2.0 (SunScan Canopy Analysis System, type SS1. Delta-T Devices Ltd. May 19, 2008)




Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
YEAR year of measurement datetime   YYYY   #N/A=Missing or Not Measured
DATE Date of measurement datetime   DD-MMM-YY   #N/A=Missing or Not Measured
SITE Toolik text     #N/A=Missing or Not Measured
GROUP Measurement location in relation to Toolik Lake LTER Shrub plots; In vicinity of Block1 = Upland, IVO Block 2 = Outlet text       #N/A=Missing or Not Measured
CANOPY Canopy sensors monitored; sensors above the canopies monitored ambient conditions for both BET and SALP vegetation text       #N/A=Missing or Not Measured
SENSOR POSN Sensor relative height text       #N/A=Missing or Not Measured
BattV_Min Minimum battery voltage during the day of measurement (battery is 12v) number volt     #N/A=Missing or Not Measured
PTemp_C_Max Maximum temperature (deg Celsius) measured by datalogger number celsius     #N/A=Missing or Not Measured
PTemp_C_TMx 24-hour time that the maximum datalogger temperature was recorded datetime   HH24:Mi   #N/A=Missing or Not Measured
PTemp_C_Avg Daily average temperature encountered by datalogger number celsius     #N/A=Missing or Not Measured
MAX TEMP Maximum temperature (deg Celsius) measured by relative humidity sensor for given canopy / position number celsius     #N/A=Missing or Not Measured
TIME OF MAX TEMP 24-hour time that maximum temperature was encountered datetime   HH24:Mi   #N/A=Missing or Not Measured
MIN TEMP Minimum temperature (deg Celsius) measured by relative humidity sensor for given canopy / position number celsius     #N/A=Missing or Not Measured
TIME OF MIN TEMP 24-hour time that minimum temperature was encountered datetime   HH24:Mi   #N/A=Missing or Not Measured
MAX RH Maximum recorded relative humidity encountered by given sensor number percent     #N/A=Missing or Not Measured
TIME OF MAX RH 24-hour time that maximum relative humidity was encountered datetime   HH24:Mi   #N/A=Missing or Not Measured
MAX PAR Maximum recorded photosynthetic active radiation (PAR) for given sensor (umol PAR per square m per sec) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
TIME OF MAX PAR 24-hour time that maximum PAR was encountered by sensor datetime   HH24:Mi   #N/A=Missing or Not Measured
DAILY TOTAL PAR Sum of PAR encountered by given sensor during the day (umol PAR per square m per day) number micromolePerMeterSquaredPerDay     #N/A=Missing or Not Measured