Comparisons between SCIAMACHY and ground-based FTIR data for total columns of CO, CH₄, CO₂ and N₂O

Total column amounts of CO, CH4, CO2 and N2O retrieved from SCIAMACHY nadir observations in ist near-infrared channels have been compared to data from a ground-based quasi-global network of Fourier-transform infrared (FTIR) spectrometers. The SCIAMACHY data considered here have been produced by three different retrieval algorithms, WFM-DOAS (version 0.5 for CO and CH4 and version 0.4 for CO2 and N2O), IMAP-DOAS (version 1.1 and 0.9 (for CO)) and IMLM (version 6.3) and cover the January to December 2003 time period. Comparisons have been made for individual data, as well as for monthly averages. To maximize the number of reliable coincidences that satisfy the temporal and spatial collocation criteria, the SCIAMACHY data have been compared with a temporal 3rd order polynomial interpolation of the ground-based data. Particular attention has been given to the question whether SCIAMACHY observes correctly the seasonal and latitudinal variability of the target species. The present results indicate that the individual SCIAMACHY data obtained with the actual versions of the algorithms have been significantly improved, but that the quality requirements, for estimating emissions on regional scales, are not yet met. Nevertheless, possible directions for further algorithm upgrades have been identified which should result in more reliable data products in a near future

Comparisons between sciamachy scientific products and ground-based FTIR data for total columns of CO, CH 4 and N 2O

Total column amounts of CO, CH 4 and N 2O retrieved from SCIAMACHY nadir observations in its near-infrared channels have been compared to data from a ground-based network of Fourier-transform infrared (FTIR) spectrometers as well as to data obtained with an FTIR instrument during a ship cruise in January-February 2003, along the African West Coast. The SCIAMACHY data considered here have been produced by two different scientific retrieval algorithms, wfm-doas (version 4.0) and IMLM (version 5.1), and cover different time periods, making the number of reliable coincidences that satisfy the temporal and spatial collocation criteria rather limited and different for both. Also the quality of the SCIAMACHY Level 1 data, and thus of the Level 2 data for the different time periods is very different. Still the comparisons demonstrate the capability of SCIAMACHY, using one of both algorithms, to deliver geophysically valuable products for the target species under consideration, on a global scale.SCOPUS: cp.pinfo:eu-repo/semantics/publishe

Guiding conservation efforts in the Hantam–Tanqua–Roggeveld (South Africa) using diversity parameters

The Hantam–Tanqua–Roggeveld subregion falls within the Succulent Karoo and Fynbos Biomes, which are both recognised as global biodiversity hotspots that should be conserved. The objective of this study was to gather baseline biodiversity information that can be used to guide conservation efforts. A total of 40 Whittaker plots were surveyed in the subregion and the various diversity parameters calculated from the data were compared across the subregion and to available data for the Succulent Karoo and Fynbos Biomes. Species richness per 1000 m2 ranged from nine to 100 species across the subregion. Species richness for all plot sizes < 1000 m2 was significantly lower for the Tanqua Karoo than for both the Winter Rainfall Karoo and Mountain Renosterveld. The latter two areas did not differ significantly from each other with regard to species richness. Species richness was significantly higher only at the 1000 m2 scale in the Mountain Renosterveld compared to the Winter Rainfall Karoo. Evenness and Shannon and Simpson indices did not differ significantly between the Mountain Renosterveld and Winter Rainfall Karoo; however, these values were significantly higher than for the Tanqua Karoo. A principal coordinate analysis of species richness data at seven plot sizes produced three distinct clusters. One cluster represented the Tanqua Karoo, with low species richness, evenness, and Shannon and Simpson indices. Another cluster represented mostly Mountain Renosterveld vegetation, which was characterised by a high species richness, evenness, and Shannon and Simpson indices. The third cluster was formed by the remaining Mountain Renosterveld plots as well as the Winter Rainfall Karoo plots. The high species richness values found in the various vegetation units can add valuable information to the conservation planning arena by providing information on biodiversity parameters and their spatial distribution. This information can assist with conservation efforts in the Hantam, Tanqua and Roggeveld areas. Conservation implications: Conservation and development of the Hantam–Tanqua– Roggeveld subregion is hampered by a lack of information on floristic diversity. The results of the current study indicated areas of low diversity and contrasting areas of high diversity. These data can be used to guide effective conservation and management of the floristic diversity