• Mission to observe distribution and changes in ecosystem function. An optical sensor with spectral discrimination greatly enhanced beyond that of Landsat and MODIS is required to detect and diagnose changes in ecosystem function, such as water and nutrient cycling and species composition. Such observations include nutrient and water status, presence of and responses to invasive species, health of coral reefs, and biodiversity. The panel proposes a hyperspectral sensor with pointability for observing disturbance events, such as fire and drought, when and where they occur at higher than normal frequency.

  • Mission to observe extent of changes in ecosystem structure and biomass. The horizontal and vertical structures of ecosystems are key features affecting carbon storage, disturbance effects, and habitats of other species. The panel proposes radar coupled with lidar to address this need. Radar has the additional advantage of being able to make observations through clouds, a key constraint in many tropical regions for observing deforestation and re-growth.

  • Carbon budget mission. The net exchange of carbon dioxide (CO2) between the atmosphere and the land and between the atmosphere and the oceans is the result of a complex set of biogeochemical processes that require improved understanding to quantify and ultimately manage the global carbon cycle. Day and night measurements of column-integrated CO2 over land, oceans, and polar regions are key to improving knowledge of the spatial and temporal patterns of biogeochemical processes that lead to surface-atmosphere exchanges of CO2. Measurement enables more complete understanding of carbon budgets because existing remote sensing capabilities address only photosynthesis and carbon exchange over sunlit regions, not the nighttime return of CO2 in respiration or air-sea gas exchange at high latitudes. The panel proposes a lidar satellite mission to measure diurnal, global atmospheric CO2 in all seasons simultaneously with pressure via column oxygen O2. Nearly simultaneous measurement of carbon monoxide (CO) to identify biomass and fossil-fuel burning is also a key component of this mission.

  • Coastal ecosystems dynamics mission. The coastal areas of oceans are an important yet poorly observed component of the Earth system. Changes on land and in the open ocean influence the ecosystem services they provide to society, such as high-protein food and healthy environments for recreation. Observations several times a day are required to capture the dynamics of coastal ecosystems. The panel proposes a hyperspectral sensor in geosynchronous orbit over the Western Hemisphere.

  • Mission on biomass and productivity of the global ocean. Quantifying the biomass and productivity of the open ocean with sufficient accuracy on climate-relevant time and space scales remains a substantial challenge. Researchers require improved optical measurements with far greater spectral resolution coupled with improved correction for atmospheric aerosols. Such measurements will be used to study ocean ecosystems and their interactions with climate and global biogeochemical cycles. The panel proposes a polar-orbiting, hyperspectral sensor through the addition of appropriate ultraviolet (UV) and visible bands to the polarimeter planned for the aerosol mission proposed by the Panel on Climate Variability and Change (see Chapter 9).

Measurements in the purview of other panels are also essential for interpreting ecosystem observations and integrating them into models. Changes in frozen and liquid water on land (soil moisture) are key measurements. Vector winds are key for analyzing ocean and coastal ecosystem dynamics. Temperature, precipitation, cloud cover, aerosols, sea-surface temperature, and ocean topographic characteristics are also vital observations.

Satellite measurements are extremely important for understanding ecosystem changes but can be fully exploited only if complemented by ground-based and aircraft-based studies. A comprehensive strategy to observe and manage ecosystems includes in situ measurements of a wide array of variables, such as pest outbreaks, fuel loads, biodiversity, agricultural yields, fertilizer application, and fluxes of atmospheric gases from land and ocean.

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