Abstract

The lack of in situ data has always posed challenges to remote-sensing-data product validation. Herein, the products of sea-ice concentration (SIC) data derived using the arctic radiation and turbulence interaction study (ARTIST) sea ice (ASI) algorithm were evaluated by comparing them with SICs from a high-resolution sea-ice aerial image obtained during the 27th China Antarctic expedition in January 2011. Results suggest that data obtained from the advanced microwave scanning radiometer for the earth-observing system (AMSR-E) underestimate SICs by 19%. We performed step-by-step comparisons among the aerial image, moderate-resolution-imaging spectroradiometer (MODIS), and AMSR-E SIC. These types of comparisons have not been made in previous validation studies. First, SICs acquired from MODIS-Terra imagery were acquired using a tie-point method and corrected by SICs derived from the aerial photography. Second, SICs of MODIS-Aqua images were trained based on the consistency of SIC results between MODIS-Terra and MODIS-Aqua over the selected region on the same day. Finally, the MODIS-Aqua SICs were employed to validate synchronous AMSR-E swath SIC products. The results show that the AMSR-E products underestimate SICs by 8.5% in the marginal ice zone in comparison with MODIS SICs. According to our further analysis between sea-ice types and AMSR-E biases, the higher the proportion of first-year ice, the smaller the AMSR-E SIC bias. In other words, results suggest that the higher the thin ice proportion, the more the AMSR-E underestimates the SIC.

Highlights

  • S ATELLITE remote-sensing data have become a crucial means of polar-climate observation since 1979 [1], [2]

  • In areas mainly covered by shelf ice or open water, AMSR-E sea-ice concentration (SIC) are generally consistent with those from the aerial image

  • Based on the synchronicity of moderate-resolution-imaging spectroradiometer (MODIS)-Aqua and AMSR-E as well as that of MODIS-Terra and the aerial image, we have presented the successive verification of passive microwave data by remote sensing visible imageries and an aerial image in a clearly structured stepby-step method

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Summary

INTRODUCTION

S ATELLITE remote-sensing data have become a crucial means of polar-climate observation since 1979 [1], [2]. The differences in SICs between passive-microwave retrieval and SIC from higher resolution measurements, such as visible light sensors and aerial images, mainly result from atmospheric water-vapor content and ice-surface melting processes in the Arctic [12]–[15]. The AMSR-E SICs released by the University of Bremen and discussed were based on the Arctic radiation and turbulence interaction study (ARTIST) sea ice (ASI) algorithm [19], [20]. Due to the similar sensor configurations and the same retrieval algorithm between AMSR-E and AMSR2, the AMSR-E ASI SICs are deemed to have better performance in the marginal ice zone than other passive-microwave SICs with lower resolutions. We applied a step-by-step validation by introducing the coincident MODIS-Aqua image to assess the swath AMSR-E SICs derived from the ASI algorithm.

Aerial Image
MODIS Data
Thin Ice Thickness
STEP-BY-STEP VALIDATION
Deriving SICs From the Composite Aerial Image
Validation of AMSR-E SICs With the Aerial Image SICs
Retrieval of MODIS-Aqua SIC by Calibrated Tie Points Using MODIS-Terra SIC
Comparison Between MODIS and AMSR-E SICs
Findings
DISCUSSION
CONCLUSION
Full Text
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