Challenges of a Sustained Climate Observing System

Abstract

Observations of planet Earth and especially all climate system components and forcings are increasingly needed for planning and informed decision making related to climate services in the broadest sense. Although signifi cant progress has been made, much more remains to be done before a fully functional and dependable climate observing system exists. Observations are needed on spatial scales from local to global, and all time scales, especially to understand and document changes in extreme events. Climate change caused by human activities adds a new dimension and a vital imperative: to acquire climate observations of suffi cient quality and coverage, and analyze them into products for multiple purposes to inform decisions for mitigation, adaptation, assessing vulnerability and impacts, possible geo-engineering, and predicting climate variability and change and their consequences. A major challenge is to adequately deal with the continually changing observing system, especially from satellites and other remote sensing platforms such as in the ocean, in order to provide a continuous climate record. Even with new computational tools, challenges remain to provide adequate analysis, processing, meta-data, archival, access, and management of the resulting data and the data products. As volumes of data continue to grow, so do the challenges of distilling information to allow us to understand what is happening and why, and what the implications are for the future. The case is compelling that prompt coordinated international actions are essential to provide for informationbased actions and decisions related to climate variability and change. Challenges of a Sustained

Simulation of Multiangular Remote Sensing Products Using Small Satellite Formations

“…Vonder Haar and Suomi [28] established that Earth's albedo was closer to 0.3 and not 0.4 as was previously thought, but further progress has not been made on albedo uncertainty. A change of 0.01 in albedo corresponds to a 3.4 W/m 2 change in reflected or absorbed sunlight (assuming outgoing radiation to be 341.3 W/m 2 [29]) which is more than half the Earth Radiation Imbalance [30], as will be described later. Climate modeling requires albedo with an absolute accuracy of 0.05, according to [31], and of 0.02 according to [32], therefore it is important to not only reduce the average albedo estimation error from measurements but also the maximum error below the stated values.…”

“…Integrating multiday measurements will increase the angular spread of measurements made by a multisensor single satellite or a single satellite formation, however, only those multiangular instruments that provide near-simultaneous angular measurements were found fit for a fair comparison. Other along-track multiangular instruments, such as Along Track Scanning Radiometer-ATSR [29] and the Advanced Spaceborne Thermal Emission and Reflection Radiometer-ASTER [30], provide only two look angles near simultaneously, therefore MISR is a best representation of along-track state-of-the-art. Cross track sensors like MODIS or Clouds and Earth's Radiant Energy System-CERES [27], provide one angular image per ground spot every hour and half, and therefore cannot be considered near-simultaneous.…”

Designing the Climate Observing System of the Future

“…Understanding aspects of climate including water usage (particularly in the food-producing regions of the world), extreme events such as hurricanes, heat waves and droughts, and sea level rise is important for society to thrive and offers substantial challenges for the science community. Targeted measurements exist to deal with some of these challenges, yet an observing system specifically designed to address these joint societal and scientific challenges has never been established (Dowell et al, 2013;National Research Council [NRC], 2007;Trenberth et al, 2013). Current international agreements only address coordination of climate observations; no commitments exist for building, and maintaining an effective climate observing system, although national efforts have supplied important components of a climate observing system (e.g., Diamond et al, 2013;World Meteorological Organization [WMO], 2015a).…”

A Satellite-Based Surface Radiation Climatology Derived by Combining Climate Data Records and Near-Real-Time Data

“…Trenberth et al [5] point out the discrepancy between the release of IPCC assessments (every six or seven years) and the need for short term assessments of the current climate. The authors state that "near-real time information and attribution is increasingly in demand, especially when major events occur".…”