Assessment of Biomass and Carbon Sequestration in Kazakhstan: Comparison of Moderate to Coarse Resolution Sensors

In the context of advancing global change science, explicit spatial data on terrestrial carbon sequestration become more and more important (IPCC, 2007). The terrestrial carbon cycle is a highly dynamic system that includes several storage pools and such components of the flux as gross primary production (GPP) and net primary production (NPP). This study attempts to fill knowledge gaps in the long-term monitoring of carbon sequestration in grasslands of Kazakhstan. Our objective is the use of a modified Light Use Efficiency (LUE) model in order to expand the satellite-based assessment of NPP dynamics in the grasslands of Kazakhstan by means of coarse-resolution satellite data (NOAA AVHRR and SeaWifs) over a period of three decades. The influence of different satellite data sets on the results of NPP simulation are addressed with respect to spatial coherencey of NPP distribution and inter-annual trends of the total carbon sequestration in the study area. The modelling results are verified against other available NPP data sets derived from field studies and MODIS data. The overall distribution of NPP turned out to be more spatially and temporally consistent after inter-calibration of the satellite data. Furthermore it has been observed that the MODIS global NPP product tends to slightly underestimate high NPP-values and overestimate low NPP values for the study area.