The purpose of the Leaf Area Index and PAR Determined from KSU Light Bar Measurements study was to collect extensive non-destructive measurements of Leaf Area Index (LAI) at the flux sites during IFC-5 (August 1989). These data were collected at thirteen locations which were coincident with the surface flux measurements within the FIFE study area from July 3, 1989 through August 18, 1989. The various fractions of the Photosynthetically Active Radiation (PAR) (i.e., diffuse, reflected, transmitted and total) were measured using a Line Quantum meter from LI-COR Inc. From these fractions the ratio of reflected to total incoming PAR was computed. LAI can be estimated from light bar measurements of PAR transmittance from measurements above and below a vegetation canopy. The use of the light bar allows rapid, multiple, and repeatable measurements of LAI at the FIFE sites. This type of measurements could not be done using destructive measurements of LAI.

LAI and PAR above & below canopy measured with light bar by KSU staff science

Light bar data recorded using LICOR LI-191SA Line Quantum Sensor

The BOREAS RSS-07 team collected various data sets to develop and validate an algorithm to allow the retrieval of the spatial distribution of LAI from remotely sensed images. Ground measurements of LAI and FPAR absorbed by the plant canopy were made using the LAI-2000 and TRAC optical instruments during focused periods from 09-AUG-1993 to 19-SEP-1994. The measurements were intensive at the NSA and SSA tower sites, but were made just once or twice at auxiliary sites.

The AirMISR BARC 2001 data were acquired during a flight over the Beltsville Agricultural Research Center (BARC) on July 21, 2001. The Jet Propulsion Laboratory (JPL) in Pasadena, California provided the data. The Airborne Multi-angle Imaging SpectroRadiometer (AirMISR) is an airborne instrument for obtaining multi-angle imagery similar to that of the satellite-borne Multi-angle Imaging SpectroRadiometer (MISR) instrument, which is designed to contribute to studies of the Earth's ecology and climate. AirMISR flies on the NASA ER-2 aircraft. The Jet Propulsion Laboratory in Pasadena, California built the instrument for NASA. Unlike the satellite-borne MISR instrument, which has nine cameras oriented at various angles, AirMISR uses a single camera in a pivoting gimbal mount. A data run by the ER-2 aircraft is divided into nine segments, each with the camera positioned to a MISR look angle. The gimbal rotates between successive segments, such that each segment acquires data over the same area on the ground as the previous segment. This process is repeated until all nine angles of the target area are collected. The swath width, which varies from 11 km in the nadir to 32 km at the most oblique angle, is governed by the camera's instantaneous field-of-view of 7 meters cross-track x 6 meters along-track in the nadir view and 21 meters x 55 meters at the most oblique angle. The along-track image length at each angle is dictated by the timing required to obtain overlap imagery at all angles, and varies from about 9 km in the nadir to 26 km at the most oblique angle. Thus, the nadir image dictates the area of overlap that is obtained from all nine angles. A complete flight run takes approximately 13 minutes. The 9 camera viewing angles are: 0 degrees or nadir 26.1 degrees, fore and aft 45.6 degrees, fore and aft 60.0 degrees, fore and aft 70.5 degrees, fore and aft. For each of the camera angles, images are obtained at 4 spectral bands. The spectral bands can be used to identify vegetation and aerosols, estimate surface reflectance and ocean color studies. The center wavelengths of the 4 spectral bands are: 443 nanometers, blue 555 nanometers, green 670 nanometers, red 865 nanometers, near-infrared Two types of AirMISR data products are available - the Level 1 Radiometric product (L1B1) and the Level 1 Georectified radiance product (L1B2).

This data set includes solar surface irradiance from Kipp and Zonen CM-21 pyranometers, both total unfiltered and filtered (RG695), and photosynthetically active radiation (PAR) from Skye-Probetech SKE-510 PAR sensors. Measurements were made at six sites acrosss the Brazilian Amazon during the period from 1999 to 2004. These sites were co-located with AERONET (AErosol RObotic NETwork) program sites. There are 17 comma-delimited data files (.csv) with this data set. The AERONET program is an inclusive federation of ground-based remote sensing aerosol networks established by AERONET and the PHOtometrie pour le Traitement Operationnel de Normalisation Satellitaire (PHOTONS) and greatly expanded by AEROCAN (the Canadian sunphotometer network) and other agency, institute and university partners. The goal is to assess aerosol optical properties and validate satellite retrievals of those properties. The network imposes standardization of instruments, calibration, and processing.

The Surface Temperatures, Reflected and Emitted Radiation, and PAR from UNL Data Set contains surface temperatures at different view zenith and azimuth angles, net radiation, incoming and reflected photosynthetically active radiation, incoming and reflected shortwave radiation, and reflected and emitted longwave radiation. Surface temperatures were measured at a 30 degree view zenith angle with an Everest infrared thermometer (IRT) Model 112C and at approximately a 60 degree view zenith angle with a Scheduler Plant Stress Monitor at 4 view azimuths (predominantly 90 degree increments from the solar azimuth). The Scheduler also measured air temperature, relative humidity, and vapor pressure deficit. Net radiation was measured with a Radiation and Energy Balance Systems (REBS) net radiometer Model Q*3. Incoming shortwave radiation was measured with a horizontally mounted Eppley Precision Pyranometer Model PSP. Reflected shortwave radiation was measured with two (2) Eppley Precision pyranometers Model PSP usually mounted horizontally (at site 966 (2437-PSP) one PSP was mounted horizontally and the other was inclined parallel to the slope). Reflected and emitted longwave radiation were measured with a horizontally mounted Eppley Precision Infrared Radiometer Model PIR.

The SE-590 Leaf Level Spectral Observations from GSFC Data Set were acquired in situ with a Spectron SE590 spectroradiometer fitted with the 1 degree IFOV lens, and coupled with a LI-COR integrating sphere. The purpose in collecting SE590 leaf reflectance and transmittance data was to characterize the optical properties of the canopy components to gain a better understanding of how these optical properties contribute to canopy reflection and absorption of radiation. To measure the reflectance and transmittance of leaf surfaces an integrating sphere was used. The integrating sphere collected all of the radiation reflected from or transmitted through a surface. These data are the average spectral optical properties (i.e., reflectance, transmittance) and the standard deviations for the three dominant species found on each of three sites: 916 (i.e., Big Bluestem, Indiangrass, and Switchgrass), 906 (i.e., Big Bluestem, Indiangrass, and Switchgrass), and 26 (i.e., Big Bluestem, Lovegrass and Dropseed) during late July and early August, 1989. The average spectral reflectance and transmittance represent the mean values for the adaxial (top) and abaxial (bottom) sides of 4 - 10 leaves for wavelengths between 400 - 1050 nm at approximately 3 nm intervals.

Leaf optical properties (reflectance & transmittance) from SE590 & LICOR

This data set provides the results of spectral reflectance (350 to 2,500 nm at 1-nm increments) and biophysical measurements on grass pastures in eight cattle ranches in the state of Rondonia, located in the southwestern Brazilian Amazon. The ranches are located near the cities of Porto Velho, Ariquemes, Ouro Preto, Ji-Parana, and Presidente Medici. Field measurements were collected in July and August 2003. The primary grass species sampled were Brachiaria brizantha and Brachiaria decumbens. Spectrometer measurements were taken at 5-m intervals along 100 m transects on the pastures - fourteen total transects. Vegetation was sampled at 20-m intervals along the transects. All standing biomass and litter on the soil surface were collected and separated into live and senesced biomass and then dried to calculate water content. Sixty-eight reflectance spectra coincided with grass biophysical samples.Note that the research was done on private lands in Rondonia, and to protect the privacy of those land owners no geographic information is associated with the reported measurements. Three data files are included: an ENVI spectral library file with reflectance data for 484 pasture sampling points, an ASCII comma-separated file with reflectance data for the 484 pasture sampling points, and an ASCII comma-separated file with the biophysical measurements.