Publications by authors named "Nathan T Kurtz"

2 Publications

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The Ice, Cloud, and Land Elevation Satellite - 2 Mission: A Global Geolocated Photon Product Derived From the Advanced Topographic Laser Altimeter System.

Remote Sens Environ 2019 Nov;233

NASA Goddard Space Flight Center, Greenbelt, MD United States.

The Ice, Cloud, and land Elevation Satellite - 2 (ICESat-2) observatory was launched on 15 September 2018 to measure ice sheet and glacier elevation change, sea ice freeboard, and enable the determination of the heights of Earth's forests. ICESat-2's laser altimeter, the Advanced Topographic Laser Altimeter System (ATLAS) uses green (532 nm) laser light and single-photon sensitive detection to measure time of flight and subsequently surface height along each of its six beams. In this paper, we describe the major components of ATLAS, including the transmitter, the receiver and the components of the timing system. We present the major components of the ICESat-2 observatory, including the Global Positioning System, star trackers and inertial measurement unit. The ICESat-2 Level 1B data product (ATL02) provides the precise photon round-trip time of flight, among other data. The ICESat-2 Level 2A data product (ATL03) combines the photon times of flight with the observatory position and attitude to determine the geodetic location (i.e. the latitude, longitude and height) of the ground bounce point of photons detected by ATLAS. The ATL03 data product is used by higher-level (Level 3A) surface-specific data products to determine glacier and ice sheet height, sea ice freeboard, vegetation canopy height, ocean surface topography, and inland water body height.
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November 2019

Estimation of sea-ice thickness and volume in the Sea of Okhotsk based on ICESat data.

Ann Glaciol 2018 Jul 5;59(76 Pt 2):101-111. Epub 2018 Apr 5.

Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan.

Sea-ice thickness in the Sea of Okhotsk is estimated for 2004-2008 from ICESat derived freeboard under the assumption of hydrostatic balance. Total ice thickness including snow depth ( ) averaged over 2004-2008 is 95 cm. The interannual variability of is large; from 77.5 cm (2008) to 110.4 cm (2005). The mode of varies from 50-60 cm (2007 and 2008) to 70-80 cm (2005). Ice thickness derived from ICESat data is validated from a comparison with that observed by Electromagnetic Induction Instrument (EM) aboard the icebreaker near Hokkaido, Japan. Annual maps of reveal that the spatial distribution of is similar every year. Ice volume of 6.3 × 10 m is estimated from the ICESat derived and AMSR-E derived ice concentration. A comparison with ice area demonstrates that the ice volume cannot always be represented by the area solely, despite the fact that the area has been used as a proxy of the volume in the Sea of Okhotsk. The ice volume roughly corresponds to that of annual ice production in the major coastal polynyas estimated based on heat budget calculations. This also supports the validity of the estimation of sea-ice thickness and volume using ICESat data.
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July 2018