Microwave Remote Sensing of Snowpack Do-Hyuk “DK” Kang Postdoctoral Fellow Northern Hydrometeorology Group (NHG) Environmental Science and Engineering University of Northern BC February 5 th 2013 Northern Hydrometeorology Group, UNBC Discovery and Acceleration Fund

Outline  Fundamentals of remote sensing  Satellites and sensors  Application of remote sensing  Remote sensing of snow in the Cariboo Mountains of BC (Jinjun Tong)  Microwave Remote Sensing  Results (DK and Déry)

 Remote Sensing is a technology for sampling electromagnetic radiation to acquire and interpret non-immediate geospatial data from which to extract information about features, objects, and classes on the Earth's land surface, oceans, and atmosphere (and, where applicable, on the exteriors of other bodies in the solar system, or, in the broadest framework, celestial bodies such as stars and galaxies).

 Energy Source or Illumination (A)  Radiation and the Atmosphere (B)  Interaction with the Target (C)  Recording of Energy by the Sensor (D)  Transmission, Reception, and Processing (E)  Interpretation and Analysis (F)  Application (G)

Electromagnetic Radiation

Interactions with the Atmosphere ScatteringAbsorbing

Those areas of the spectrum which are not severely influenced by atmospheric absorption and thus, are useful to remote sensors, are called atmospheric windows

Target Interactions  Absorption (A) occurs when radiation (energy) is absorbed into the target while transmission (T) occurs when radiation passes through a target. Reflection (R) occurs when radiation "bounces" off the target and is redirected.

 water and vegetation may reflect somewhat similarly in the visible wavelengths but are almost always separable in the infrared.

Passive vs. Active Remote Sensing Passive SensingActive Sensing

Satellites and Sensors  In order for a sensor to collect and record energy reflected or emitted from a target or surface, it must reside on a stable platform removed from the target or surface being observed. Platforms for remote sensors may be situated on the ground, on an aircraft or balloon (or some other platform within the Earth's atmosphere), or on a spacecraft or satellite outside of the Earth's atmosphere. Although ground-based and aircraft platforms may be used, satellites provide a great deal of the remote sensing imagery commonly used today.

Satellite Orbits Geostationary orbits Near-polar orbit Ascending vs Descending

Weather Satellites/Sensors  TIROS-1(launched in 1960 by the United States)  GOES (Geostationary Operational Environmental Satellite) -GOES-1 (launched 1975), GOES-8 (launched 1994)  Advanced Very High Resolution Radiometer(NOAA AVHRR)(sun- synchronous, near-polar orbits)  FengYun-1, FengYun-2, FengYun-3, FengYun-4 (China)  GMS (Japan)  Meteosat (European)

Land Observation Satellites/Sensors  Landsat (Landsat-1 was launched by NASA in 1972, near-polar, sun-synchronous orbits). -Return Beam Vidicon (RBV), MultiSpectral Scanner (MSS), Thematic Mapper (TM)  SPOT(SPOT-1 was launched by France in 1986, sun-synchronous, near-polar orbits) -Twin high resolution visible (HRV)  Multispectral Electro-optical Imaging Scanner(MEIS II) Compact Airborne Spectrographic Imager(CASI)(airborne sensors)(Canada)  Canadian RADARSAT I and II - (Active Microwave Remote Sensing)

Data Reception, Transmission, and Processing In Canada, CCRS operates two ground receiving stations - one at Cantley, Québec (GSS), just outside of Ottawa, and another one at Prince Albert, Saskatchewan (PASS)

Quiz

 It is one of 13 main sub-basins in the Fraser River Basin, one of the world's most productive salmon river systems.  Snow plays a vital role in the energy and water budgets of these basins. The Quesnel River Basin (QRB) in the Cariboo Mountains

Evaluation of MODIS data SnowNo snow Snowab No snowcd Ground MODIS Accuracy of different MODIS snow data StationsElevation, m MOD10A1, %MOD10A2, %SF, % Horsefly Lake/Gruhs Lake Barkerville Boss Mountain Mine Yanks Peak East

The spatially filtered snow cover fraction (SCF) for different elevation bands (top) and aspects with slopes > 15 o (bottom), Results Snow cover fraction (%)

The mean elevational dependence of snow cover fraction (SCF) for the months of February to July,

The annual snow cover duration ( x 3 days) in the QRB based on spatially filtered (SF) MODIS snow products, r = 0.96 d(SCD)/dz = 11.6 days (100 m) -1 SCD (days) Mean snow cover durations (SCD) for 10-m elevation bands from the MOD10A2 (+) & SF ( □ ) products,

Scatter plot between average air temperature and SCF 50% (top) and scatter plot between SCF 50% & R 50% during spring for the QRB, (bottom).

Quiz

Snow Microwave Sensors  SMMR ( scanning multichannel microwave radiometer ) - It measured dual-polarized microwave radiances, at 6.63, 10.69, 18.0, 21.0, and 37.0 GHz, from the Earth's atmosphere and surface.  SSM/I ( special sensor microwave/imager ) - The instrument measures surface/atmospheric microwave brightness temperature (TBs) at 19.35, , 37.0 and 85.5 GHz.  AMSR-E ( Advanced Microwave Scanning Radiometer-EOS) channels and 6 frequencies ranging from 6.9 to 89.0 GHz. H-pol. and V-pol.

Energy Flux VS Intensity  Energy flux is defined by the energy flow with a given area [W/m 2 ]  Intensity is defined by the energy flow per a given area, a given frequency, and a given solid angle [W/m 2 Hz Steradian ] – a physically imaginary term but important for the interpretation in Remote Sensing

Fraser River  Snow Dominant Watershed

1 mm grids, Salminen et al. 2009

Quiz

Passive vs. Active Sensing

Frolov and Marchert 1999, Hallikainen et al. 1986, TGRS

Key Words Matzler and Wiesmann 1999 Devonec and Barros 2002 TbTb TsTs p ec freq LWC Brightness Temperature Absorption Coeffi. Scattering Coeffi. Real Permittivity Imaginary Permittivity

Schanda and Matzler 1981 Willis et al RS and Env Kang et al Accepted in IEEE

Derksen et al RS env

Derksen et al. 2005, Chang et al. 1987

Time series (left) and scatter plots (right) of the observed & retrieved SWE from algorithms using different AMSR-E channel combinations at Yanks Peak East from

Conclusions  Use Remote Sensing to cover global scale monitoring of snowpack  Visible and Microwave Remote Sensing of Snowpack  Reflectance and Microwave Radiometry  Antenna Response Model VS Radiometry observation  Wave signatures VS Snow physical properties