ATSR Reprocessing for Climate: Lake Surface Water Temperature & Ice Cover (ARC-Lake)

Introduction

The Earth Observing missions of the European Space Agency (ESA) include many sensors with unique technical specifications and capabilities. Among these are the series of (Advanced) Along Track Scanning Radiometers, (A)ATSRs, and their future successors the Sea and Land Surface Temperature Radiometers (SLSTRs).

ARC-Lake is an ESA funded project that aims:

• to use the exceptional radiometric qualities and dual-view scanning capability of the (A)ATSRs to derive observations of Lake Surface Water Temperature (LSWT) and Lake Ice Cover (LIC), for major lakes, globally, for 1991 – 2010; and
• to demonstrate the usefulness of these observations to climate science.

But why is a project of this nature required? Lakes are a distinct category of target for remote sensing, and attempts to deliver LSWT as a by-product of sea surface temperature (SST) retrieval or land surface temperature (LandST) retrieval have not delivered sufficiently convincing results. Nonetheless, the potential exists for (A)ATSR LSWT/LIC to be a major contribution to monitoring of lakes within the Global Climate Observing System, because the (A)ATSRs are in principle capable to be a highly accurate source of information on LSWTs on a systematic global basis. The focus on lakes via this project will unlock that potential, and will facilitate further climatological and environmental studies.

LSWT and LIC observations have potential environmental and meteorological applications for inland water management and numerical weather prediction (NWP). They also offer the basis of a long term record of the physical state of lakes. Assuming ARC-Lake gives a successful demonstration, it is hoped that routine lake observations will continue through future Sentinel missions.