3. issues relating to the effectiveness of the Distributed Active Archive Center (DAACs) and their data distribution activities.
Table 3-1 compared the science-driving questions to the types of measurements needed to address the questions and Chapter 4 then assessed available data sets and whether they are adequate to fully support the ESE. Chapter 4 then concluded with a discussion of specific measurements that would enhance NASA's present and future contributions to ESE science. In this section, the committee presents its view of the highest priorities for measurement in the cryosphere1 and data set assessment based on (1) previously identified gaps between data needs and availability; (2) the potential scientific payoffs if these gaps are filled; and (3) the feasibility and likelihood of significant progress over the next several years. The measurements identified here are generally the ones that appear repeatedly in Table 3-1, but are currently lacking or deficient in ways that present significant obstacles to progress on the fundamental ESE science issues. These 10 high-priority measurements are:
freshwater discharge from terrestrial regions,
all-sky surface temperature,
surface turbulent fluxes,
ocean surface salinity,
ice sheet mass flux,
land surface characteristics, and
sea ice thickness.
In some cases, products that appear to be lacking (e.g., surface radiation fluxes) are under development with current sensors, so these are not included in this list. For all variables, the need is for data sets sufficient to determine the spatial and temporal variations. For those variables deemed suitable for monitoring, temporal continuity across instruments must be a key consideration.
1 The committee's deliberations and this list of 10 high priority measurements focuses directly on the cryosphere (i.e., surface characteristics) and the fluxes that determine cryospheric characteristics.