Based on our experience with SCIAMACHY, a two channel grating spectrometer system was developed. Similar as SCIAMACHY, the spectrometer covers important parts of the near infrared (NIR) / short wave infrared (SWIR) spectral region (around 1600 nm, 1660 nm and 760 nm) for CO2, CH4 and O2 measurements. The instrument has been designed for flexible operation on board of different airborne research platforms (e.g. DLR Dornier 228, DLR Falcon, Cessna Caravan, Cessna 207 and for the future DLR Gulfstream HALO aircraft).
Different laboratory, ground based and airborne measurements have been performed demonstrating the instruments performance.
The instrument is designed to measure the column averaged mixing ratio of CH4 and CO2 (i.e. XCH4 and XCO2) with a relative accuracy and precision of equal or better than ~1% with respect to the atmospheric background concentration (see also Gerilowski et al., 2011, Krings et al. 2011). Working in the SWIR spectral region (1.630 -1.675 µm for CH4 and 1.59-1.62 µm for CO2) the instrument has a high sensitivity for small changes in the boundary and surface layer CH4 and CO2 concentration.
At a flight altitude of 3 km and a ground speed of 300 km/h (DLR Do 228 aircraft), the co-added ground pixel size is in the order of 50 m (across track) x 100 m (along track) over land (surface albedo 0.18). Over water a similar pixel size (and precision) was achieved when the instrument is operated in Solar Glint-mode geometry. By reducing the dark current of the sensor head (sensor dark current + ambient thermal dark current) below 60 fA the instrument is able to reach a S/N ratio of ~1000 over land for an integration time of 1 sec.
Due do the high accuracy, the high sampling speed and the small pixel size of 50 m along track at a ground speed of 300 km/h (DLR Do 228 aircraft), MAMAP can also easily be adopted as a passive airborne optical remote sensing system for natural gas pipeline leak detection which will reduce the time and cost of leak detection by providing "near real time" methane data.
