Cubesats for monitoring atmospheric processes (CubeMAP): a constellation mission to study the middle atmosphere

Some aspects of the CubeMAP mission (also known as ESP-MACCS) are presented: its science objectives, and the primary choices made to address them from small satellite platforms. The science case, addressing some key scientific questions related to global change, is elaborated in four objectives focused on upper troposphere and stratospheric composition and its change. The sounding methodology and the associated observation concept retained is a constellation of miniature limb solar occultation thermal infrared sounders, offering the advantages of limb solar occultation, whilst mitigating the inherent lack of coverage of this geometry. The mission focuses on tropical regions as the gateway to the upper troposphere, and the stratosphere. The miniaturized instrument payloads developed for the mission are briefly presented: the High resolution InfraRed Occultation Spectrometer (HIROS) and the Hyperspectral Solar Disk Imager (HSDI). Lastly, the nanosatellite 12U platform and its subsystem are described, completing the overview of the mission space segment

LOCUS: Low cost upper atmosphere sounder

We present the results of an instrument concept study for a low cost terahertz sounder of the mesosphere and lower thermosphere (MLT). Recent advances in the development of Quantum Cascade Laser (QCL) technology to be used for Local Oscillators (LOs) mean that it has now become viable for the first time to build compact, low weight heterodyne receivers in the terahertz (THz) frequency range [28]. Some of the most important atmospheric constituents of the MLT region, e.g. atomic oxygen (O) and the hydroxyl radical (OH), can only realistically be measured at THz frequencies. The technical challenges of THz remote sensing result in a large uncertainly of the global distribution of these species. Recent research indicates that the MLT region exhibits links to processes associated with climate change. From this follows a strong need to measure the composition and dynamic of the MLT region more accurately and more comprehensively

Unexpectedly large impact of forest management and grazing on global vegetation biomass

Carbon stocks in vegetation have a key role in the climate system1,2,3,4. However, the magnitude, patterns and uncertainties of carbon stocks and the effect of land use on the stocks remain poorly quantified. Here we show, using state-of-the-art datasets, that vegetation currently stores around 450 petagrams of carbon. In the hypothetical absence of land use, potential vegetation would store around 916 petagrams of carbon, under current climate conditions. This difference highlights the massive effect of land use on biomass stocks. Deforestation and other land-cover changes are responsible for 53–58% of the difference between current and potential biomass stocks. Land management effects (the biomass stock changes induced by land use within the same land cover) contribute 42–47%, but have been underestimated in the literature. Therefore, avoiding deforestation is necessary but not sufficient for mitigation of climate change. Our results imply that trade-offs exist between conserving carbon stocks on managed land and raising the contribution of biomass to raw material and energy supply for the mitigation of climate change. Efforts to raise biomass stocks are currently verifiable only in temperate forests, where their potential is limited. By contrast, large uncertainties hinder verification in the tropical forest, where the largest potential is located, pointing to challenges for the upcoming stocktaking exercises under the Paris agreement