Applications of Remote Sensing: The Cryosphere (Snow & Ice) Menglin Jin, San Jose Stte University Outline  Physical principles  International satellite sensors enabling remote sensing of tropospheric aerosols –ESMR, SMMR, SSM/I, AVHRR, MODIS, AMSR  Instrument characteristics –Spacecraft, spatial resolution, swath width, sensor characteristics, and unique characteristics  Sea ice and snow retrieval from existing satellite systems  Future capabilities  Opportunities for the future Credit: Michael D. King, NASA GSFC

 Sparsely distributed ice floes as viewed from a ship in the Bering Sea Sea Ice of Different Forms and Perspectives Photograph courtesy of Claire Parkinson

 Expansive ice field, as viewed from an aircraft in the central Arctic Sea Ice of Different Forms and Perspectives Photograph courtesy of Claire Parkinson

 Close-up of newly formed ice in the Bering Sea Sea Ice of Different Forms and Perspectives Photograph courtesy of Claire Parkinson

 Ice floes separated by a lead, as viewed from an aircraft over the central Arctic Sea Ice of Different Forms and Perspectives Photograph courtesy of Claire Parkinson

 Thin sheets of ice, as viewed from an aircraft Sea Ice of Different Forms and Perspectives Photograph courtesy of Koni Steffen

 Several-months-old ice bearing the weight of a helicopter, as viewed from ground level in the Bering Sea Sea Ice of Different Forms and Perspectives Photograph courtesy of Claire Parkinson

 Nimbus 5 –Electrically Scanning Microwave Radiometer (ESMR) »December »single channel (19 GHz = 1.55 cm) conically scanning microwave radiometer  Nimbus 7 –Scanning Multichannel Microwave Radiometer (SMMR) »October 1978-August 1987 »10 channel (five frequency and dual polarization) conically scanning microwave radiometer  Defense Meteorological Satellite Program (DMSP) –Special Sensor Microwave Imager (SSM/I) »June 1987-present »7 channel (three frequencies with both vertical and horizontal polarization + 1 frequency with horizontal polarization only) Remote Sensing of Sea Ice from Passive Microwave Radiometers

 NASA, Aqua –launches July 2001 –705 km polar orbits, ascending (1:30 p.m.)  Sensor Characteristics –12 channel microwave radiometer with 6 frequencies from 6.9 to 89.0 GHz with both vertical and horizontal polarization –conical scan mirror with 55° incident angle at Earth’s surface –Spatial resolutions: »6 x 4 km (89.0 GHz) »75 x 43 km (6.9 GHz) –External cold load reflector and a warm load for calibration »1 K T b accuracy Advanced Microwave Scanning Radiometer (AMSR-E)

 Thicker snow results in lower microwave brightness temperatures Microwave Scattering of Snow Cover From Parkinson, C. L., 1997: Earth from Above

 Higher rate of microwave emission from sea ice than from open water  Emissivities indicated are for wavelength of 1.55 cm (19 GHz) Satellite Detection of Sea Ice From Parkinson, C. L., 1997: Earth from Above

Spectra of Polar Oceanic Surfaces over the SMMR Wavelengths Wavelength (cm) Brightness Temperature (K) FY Ice V FY Ice H MY Ice V MY Ice H Open Ocean H Open Ocean V

March 8-10, 1974September 16-18, 1974 <132.5 K≥ K200 K160 K240 K140 K180 K220 K260 K Brightness Temperature of Polar Regions from Nimbus 5 ESMR T b (19 GHz) Parkinson ( 1997)

March 1986September % 80% 60% 40% 20% ≤12% Monthly Average Sea Ice Concentrations from Nimbus 7 SMMR From Parkinson, C. L., 1997: Earth from Above

March 1986September % 80% 60% 40% 20% ≤12% Monthly Average Sea Ice Concentrations from Nimbus 7 SMMR From Parkinson, C. L., 1997: Earth from Above

February 1999September % 80% 60% 40% 20% ≤12% Monthly Average Sea Ice Concentrations from SSM/I

South Polar Region North Polar Region Location Maps for North and South Polar Regions From Parkinson, C. L., 1997: Earth from Above

Decreases in Arctic Sea Ice Coverage as Observed from Satellite Observations C. L. Parkinson, D. J. Cavalieri, P. Gloersen, H. J. Zwally, and J. C. Comiso, 1999: J. Geophys. Res. November December 1996

Monthly Arctic Sea Ice Extent Deviations –34300 ± 3700 km 2 /year C. L. Parkinson, D. J. Cavalieri, P. Gloersen, H. J. Zwally, and J. C. Comiso, 1999: J. Geophys. Res.

Yearly and Seasonal Ice Extent Trends Yearly–2.8%/decade Winter–2.2%/decade Spring–3.1%/decade Summer–4.5%/decade Autumn–1.9%/decade Trends in Arctic Sea Ice Coverage C. L. Parkinson, D. J. Cavalieri, P. Gloersen, H. J. Zwally, and J. C. Comiso, 1999: J. Geophys. Res. Data Sources  For November 1978 – August 1987, the Scanning Multichannel Microwave Radiometer (SMMR) on NASA’s Nimbus 7 satellite  Since mid-August 1987, the Special Sensor Microwave Imagers (SSM/Is) on satellites of the Defense Meteorological Satellite Program  37,000 km 2 /year decrease of sea ice area over a 19.4 year period observed from satellite  19,000 km 2 /year decrease in sea ice area over a 46 year period based on Geophysical Fluid Dynamics Laboratory (GFDL) model

Observed Northern Hemisphere Sea Ice Decreases Placed in a Climate Context Probability that an observed sea-ice-extent trend results from natural climate variability, based on a 5000-year control run of the GFDL General Circulation Model (GCM)  Open Circle –Observed trend, updated from Chapman and Walsh (1993)  Open Square –Observed trend, updated from Parkinson et al. (1999)

Sea Ice Trends  Probability that observed trends result from natural climate variability –1953 – 1998 trend < 0.1 % –1978 – 1998 trend < 2 %  Demonstrates how scientists have attempted to take the satellite data record and put it into context of man’s impact on climate Vinnikov, Robock, Stouffer, Walsh, Parkinson, Cavalieri, Mitchell, Garrett, and Zakharov, published in the December 3, 1999 issue of Science

19 GHz Vertical Polarization <132.5 K≥ K200 K160 K240 K140 K180 K220 K260 K Brightness Temperature of Polar Regions from SSM/I 37 GHz Vertical Polarization March 14, 1997

<132.5 K≥ K200 K160 K240 K140 K180 K220 K260 K Brightness Temperature of Polar Regions from SSM/I March 14, GHz Vertical Polarization

Brightness Temperature Scatter Diagram for Odden Region and Greenland Sea Early IceMaximum Extent of Bulge Brightness Temperature (V37) Brightness Temperature (V19) November 21, 1996 January 18, 1997 O O A A D D Odden Study Area (pancakes or nilas) Thick ice (consolidated region)

Brightness Temperature Scatter Diagram for Odden Region and Greenland Sea Maximum Extent of TongueIce Melt & Formation of Ice Island Brightness Temperature (V37) Brightness Temperature (V19) March 14, 1997April 14, 1997

Brightness Temperature of Polar Regions from SSM/I February 26, 1987 SSM/IAVHRR

Brightness Temperature of Polar Regions from SSM/I March 15, 1987 SSM/IAVHRR

 Pucahirca, Peru –October 1991 –Latitude of 9°S –Foreground altitude is 5325 m Photograph courtesy of Lonnie Thompson Snow Cover in the Northern Andes

 Nimbus 7/SMMR –Uses two horizontally polarized microwave frequencies (18 and 37 GHz) »snow scatters less at the lower frequency (longer wavelength) »the thicker the snow the greater the difference in brightness temperature between 18 and 37 GHz  z = 1.59[T b (18 GHz) – T b (37 GHz)] where z = snow thickness in cm »restricted to ice-free land with snow thickness 5 ≤ z ≤ 70 cm Remote Sensing of Snow Cover & Thickness from Passive Microwave Radiometers

February 1986 March cm 55 cm 40 cm 25 cm 10 cm ≤4 cm Monthly Average Snow Thickness from Nimbus 7 SMMR From Parkinson, C. L., 1997: Earth from Above

April 1986May cm 55 cm 40 cm 25 cm 10 cm ≤4 cm Monthly Average Snow Thickness from Nimbus 7 SMMR From Parkinson, C. L., 1997: Earth from Above

Location Map for North Polar Region From Parkinson, C. L., 1997: Earth from Above

February 1979February cm 55 cm 40 cm 25 cm 10 cm ≤4 cm Monthly Average Snow Thickness from Nimbus 7 SMMR From Parkinson, C. L., 1997: Earth from Above

 NOAA/AVHRR-3 –Uses reflectance at 1.6 µm where snow and ice absorb solar radiation much greater than water or vegetation »Advantage high spatial resolution (4 km GAC, 1.1 km LAC) »Disadvantage affected by cloud cover observations possible only at night difficult to detect snow in deep forests  Terra/MODIS –Uses reflectance at 1.6 µm –Higher spatial resolution of AVHRR (global at 1 km) –Makes use of better cloud mask for distinguishing clouds from snow and land surfaces (and shadows) Remote Sensing of Snow Cover from Shortwave Infrared Radiometers

MODIS Snow Cover Compared to Historical Snow Record (1966-present) March Average February Average Cloud March 5-12, 2000