Evaluating Hyperspectral Imager for the Coastal Ocean (HICO) data for seagrass mapping in Indian River Lagoon, FL

by on 9 June 2015in Earth Science and Remote Sensing No comment

Differentiation between benthic habitats, particularly seagrass and macroalgae, using satellite data is complicated because of water column effects plus the presence of chlorophyll-a in both seagrass and algae that result in similar spectral patterns. Hyperspectral imager for the coastal ocean data over the Indian River Lagoon, Florida, USA, was used to develop two benthic classification models, SlopeRED and SlopeNIR. Their performance was compared with iterative self-organizing data analysis technique and spectral angle mapping classification methods. The slope models provided greater overall accuracies (63?64%) and were able to distinguish between seagrass and macroalgae substrates more accurately compared to the results obtained using the other classifications methods.

Related URLs:
http://dx.doi.org/10.1080/15481603.2014.895577

Optical Algorithm for Cloud Shadow Detection Over Water

by on 9 June 2015in Earth Science and Remote Sensing No comment

The application of ocean color product retrieval algorithms for pixels containing cloud shadows leads to erroneous results. Thus, shadows are an important scene type that should be identified and excluded from the set of clear-sky pixels. In this paper, we present an optical cloud shadow-detection technique called the Cloud Shadow Detection Index (CSDI). This approach is for homogeneous water bodies such as deep waters where shadow detection is very challenging due to the relatively small differences in the brightness values of the shadows and neighboring sunlit or some other regions. The CSDI technique is developed based on the small differences between the total radiances reaching the sensor from the shadowed and neighboring sunlit regions of similar optical properties by amplifying the differences through integrating the spectra of the two regions. The Integrated Value (IV) is then normalized by the mean of the IVs within a spatial adaptive sliding box where atmospheric and marine optical properties are assumed homogeneous. Assuming that the true color and the IV images represent accurate shadow locations, the results were visually compared. The CSDI images agree reasonably well with the corresponding true color and the IV images over open ocean. Also, the shape of the cloud shadow particularly for the isolated cloud closely follows that of the cloud, as expected, reconfirming the potential of the CSDI technique.

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Columbus-External Payload Facility (Columbus-EPF)

by on 2 May 2015in Earth Science and Remote Sensing
  • External payload platform
  • 4 payload sites (1 Zenith, 1 Nadir, 2 Starboard)
  • Mass per payload 290kg
  • Power capability of 1.25 kW is provided by two 120-Vdc redundant power feeds at each attachment site
  • Maximum payload size 864 x 1168 x 1245 mm without the adapter plate

Data capabilities:

  • Low-rate 1553-B data line for status data
  • Medium-rate Ethernet data line with rates of up to 1.55 Mbps
  • High-rate data line interfaces with the video data processing unit and transmits up to 32.426 Mbps in increments of 32 kbps

Lightning Imager Sensor (LIS)

by on 2 May 2015in Earth Science and Remote Sensing
  • One of the Space Test Program (STP-H5) instruments
  • Field of View (FOV): 80 degrees x 80 degrees
  • Pixel Instantaneous FOV (IFOV): 4 km
  • Measurement Accuracy
    • Location: 1 pixel
    • Intensity: 10%
    • Time: Tag at frame rate
  • Interference filter
    • Wavelength 777.4 nm
    • Bandwidth 1 nm
  • Detection threshold 4.7 µJ m-2 sr-1
  • CCD array size 128 x 128 pixels
  • Dynamic range >100
  • Detection efficiency ~90%
  • False event rate <5%
  • Dimensions
    • Sensor head assembly 20 x 37 cm
    • Electronics box 31 x 22 x 27 cm
  • Instrument mass 20 kg
  • Instrument power 30 W
  • SNR (Signal to Noise Ratio) 6
  • Telemetry data rate 8 kbit/s
  • Telemetry format PCM (Pulse Code Modulation)

ISS-RapidScat

by on 2 May 2015in Earth Science and Remote Sensing

Specifications

Instrument

  • SeaWinds Scatterometer (Pencil Beam Scatterometer)
  • Antenna Diameter: 0.75 m
  • Mounted on Columbus Module

System Parameters (courtesy of NASA’s JPL)

  • Orbital Attitude : 435km
  • Antenna Size: 0.75m
  • 3 dB beamwidth – 1 way – elevation: 2.4, 2.2 degree
  • 3 dB beamwidth – 1 way – azimuth: 2.1 degree
  • Antenna Rotation Rate: 18rpm
  • Operating Frequency: 13.4 GHz
  • Chirp Rate: 250 kHz/ms
  • Pulse Width: 1.0 ms
  • PRI: 6.0 ms
  • Peak Radiated Power: 80 W
  • Incidence Angle, 2 Beams: 49.56 degree
  • Ground-range Resolution: 0.79, 0.73 km
  • Azimuth Resolution: 15.5, 17.3 km
  • Slant Range: 600, 678 km
  • Ground Swath: 900, 1100 km
  • Data Window Length: 1.4 ms
  • NE sigma0: -32.8, -31.5 dB

Cloud-Aerosol Transport System (CATS)

by on 2 May 2015in Earth Science and Remote Sensing

Specifications

  • CATS operates in three different modes.  Mode 1 is the primary operating mode; Modes 2 and 3 are used periodically.

Sensor

  • Light detection and ranging (LiDAR)

Spectral Bands

  • Operational Mode 1: Multi-beam mode splits the energy from the first laser into two wavelengths that represent near infrared radiation (1064 nanometers) and visible light (532 nanometers) for determining layer type (i.e., cloud and aerosol composition).
  • Operational Mode 2: Uses the second laser and to demonstrate a new technology called High Spectral Resolution Lidar (HSRL). This new technique uses a narrower wavelength interval at 1064 and 532 nanometers to provide more precise measurements. The will provide better estimates of extinction, which is extremely important for model applications since it is an important variable in determining the radiative effects of clouds and aerosols on the climate system.
  • Operational Mode 3: Uses the second laser, in addition to operating at 1064 and 532 nanometers, adds a third wavelength at 355 nanometers. The shorter wavelength of 355 nanometers lies in the ultraviolet region of the electromagnetic spectrum and will therefore interact with particles differently than 1064 and 532 nanometer wavelengths.

ISS SERVIR Environmental Research and Visualization System (ISERV)

by on 2 May 2015in Earth Science and Remote Sensing

Sensor

  • Celestron CPC-925 telescope with shorter fork arms from a CPC-800. 9.25″ telescope uses the HyperStar lens to operate at a fast f/2.3 focal ratio
  • Canon EOS 7D digital SLR is mounted on the HyperStar lens to capture images
  • Nadir Spatial Resolution: resolution of 10 feet per pixel, but gives a field of view 19 km x 11 km area
  • Spectral Bands: Visible to near IR
  • Pointing: WORF facility in the Destiny Laboratory Window