A novel satellite mission concept for upper air water vapour, aerosol and cloud observations using integrated path differential absorption LiDAR limb sounding

We propose a new satellite mission to deliver high quality measurements of upper air water vapour. The concept centres around a LiDAR in limb sounding by occultation geometry, designed to operate as a very long path system for differential absorption measurements. We present a preliminary performance analysis with a system sized to send 75 mJ pulses at 25 Hz at four wavelengths close to 935 nm, to up to 5 microsatellites in a counter-rotating orbit, carrying retroreflectors characterized by a reflected beam divergence of roughly twice the emitted laser beam divergence of 15 µrad. This provides water vapour profiles with a vertical sampling of 110 m; preliminary calculations suggest that the system could detect concentrations of less than 5 ppm. A secondary payload of a fairly conventional medium resolution multispectral radiometer allows wide-swath cloud and aerosol imaging. The total weight and power of the system are estimated at 3 tons and 2,700 W respectively. This novel concept presents significant challenges, including the performance of the lasers in space, the tracking between the main spacecraft and the retroreflectors, the refractive effects of turbulence, and the design of the telescopes to achieve a high signal-to-noise ratio for the high precision measurements. The mission concept was conceived at the Alpbach Summer School 2010

A method to establish marine bio-regions in the pelagic ecosystem based on phytoplanktonic communities. Aplication to the southern Spanish coast

Bioregions in the pelagic ecosystem are frequently established on the basis of remotely sensed properties of the sea surface, such as sea surface temperature or sea surface chlorophyll concentration. Those works dealing with the regionalization of the marine ecosystem by means of the use of properties of the water column are less frequent, and even less those that obtain the data from periodic in situ monitoring programs, which are scarce. In this work we use time series of micro, nano and pico-phytoplanktonic abundances in the upper 100 m of the continental shelves of the Gulf of Cadiz and the Alboran Sea from the projects STOCA and RADMED (southern coast of Spain, Western Mediterranean). The use of times series allows us to estimate the median phytoplanktonic abundances of several phytoplanktonic groups along the water column. These statistics differ substantially from those abundances obtained for one particular campaign, reflecting the large seasonal and inter-annual variability of phytoplanktonic communities. These median profiles, estimated for the four seasons of the year and for several phytoplanktonic groups characterize each of the locations sampled in the aforementioned monitoring programs and are used for establishing the similarity between them. Then, these locations are grouped using a cluster analysis. Using some simulations from numerical experiments we determine which metrics and methods of analysis are the more suitable ones for the regionalization of the area of study. A bootstrap method is also used to determine which differences among bioregions can be considered as statistically significant. Despite the existence of a fast current that connects the Gulf of Cadiz and the Alboran Sea, our results show that the outer part of the Gulf of Cadiz shelf, and that of the Alboran Sea, can be considered as two differentiated bioregions. The latter region shows a higher productivity with a higher abundance of large cells such as diatoms, and the dominance of Synechococcus bacteria over Prochlorococcus ones

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead