Second-order structure function analysis of scatterometer winds over the Tropical Pacific

22 pages, 16 figures, 1 tableKolmogorov second-order structure functions are used to quantify and compare the small-scale information contained in near-surface ocean wind products derived from measurements by ASCAT on MetOp-A and SeaWinds on QuikSCAT. Two ASCAT and three SeaWinds products are compared in nine regions (classified as rainy or dry) in the tropical Pacific between 10°S and 10°N and 140° and 260°E for the period November 2008 to October 2009. Monthly and regionally averaged longitudinal and transverse structure functions are calculated using along-track samples. To ease the analysis, the following quantities were estimated for the scale range 50 to 300 km and used to intercompare the wind products: (i) structure function slopes, (ii) turbulent kinetic energies (TKE), and (iii) vorticity-to-divergence ratios. All wind products are in good qualitative agreement, but also have important differences. Structure function slopes and TKE differ per wind product, but also show a common variation over time and space. Independent of wind product, longitudinal slopes decrease when sea surface temperature exceeds the threshold for onset of deep convection (about 28°C). In rainy areas and in dry regions during rainy periods, ASCAT has larger divergent TKE than SeaWinds, while SeaWinds has larger vortical TKE than ASCAT. Differences between SeaWinds and ASCAT vortical TKE and vorticity-to-divergence ratios for the convectively active months of each region are large. © 2014. American Geophysical Union. All Rights ReservedThe ASCAT-12.5 and ASCAT-25 data used in this work can be ordered online from the EUMETSAT Data Centre (www.eumetsat.int) as SAF type data in BUFR or NetCDF format. They can also be ordered from PO.DAAC (podaac.jpl.nasa.gov) in NetCDF format only. The SeaWinds-NOAA and QuikSCAT-12.5 data are also available from PO.DAAC. The SeaWinds-KNMI data are available from the KNMI archive upon an email request to [email protected]. Rain-rates and sea surface temperatures were obtained from the Tropical Rainfall Measuring Mission's (TRMM) Microwave Imager (TMI) archive at the Remote Sensing Systems web site (www.ssmi.com). SeaWinds Radiometer (SRAD) rain-rates were obtained from the QuikSCAT 25 km L2B science data product that is available from PO.DAAC. This work has been funded by EUMETSAT in the context of the Numerical Weather Prediction Satellite Applications Facility (NWP SAF). The contribution of GPK has been supported by EUMETSAT as part of the SAF Visiting Scientists programmePeer Reviewe

On the utilization of meso-scale models for offshore wind atlases

Two different offshore wind atlases based on the meso-scale model WRF are presented and discussed in this paper. The Work is part of the EU-funded project NORSEWIND (Northern Seas Wind Index Database). Validations show that annual average wind speeds and windroses at hub-height (100m) are well represented by the model, while the model accuracy is poorer for vertical wind profile, wind shear parameters and static stability

Identifying coffee: development of a low-cost and robust barcoding assay for wild African Coffea species

With an estimated consumption of more than two billion cups a day, coffee is one of the most popular beverages in the world. Nearly all coffee is produced from the seeds of two species: Coffea arabica (Arabica coffee) and Coffea canephora (Robusta coffee). Both Arabica and Robusta coffee production is threatened by climate fluctuations and disease outbreaks, reducing yields and ravaging coffee plantations. To overcome these challenges, the potential of other wild Coffea species for the improvement of existing coffee varieties or for the development of new varieties has been studied. The Coffea genus consists of circa 130 described species that are mainly found in sub-Saharan Africa and Madagascar. Coffea species on the African continent are more closely related to Arabica and Robusta coffee. Nevertheless, the identification of African Coffea species at species level based on morphological traits can be challenging as several species seem to have overlapping trait characteristics. In this study, we developed a molecular barcoding assay consisting of eight nuclear markers between ca 200 and 800 base pairs long that can be sequenced using Sanger sequencing. Marker regions were selected based on the output of publicly available genotyping-by-sequencing data, ensuring that each Coffea species included in this dataset had a unique allele for at least two out of eight markers. The resulting barcoding assay is a cost-efficient and accessible tool for the molecular identification of wild African Coffea species, facilitating their conservation and their application for the improvement of coffee cultivation

Détermination des zones potentielles de conservation de la biodiversité : un aperçu sur l’approche méthodologique basée sur la diversité spécifique et les espèces endémiques

peer reviewe

African elements in Saramaccan Maroon plant names in Suriname

The ancestors of the Saramaccan Maroons, who were brought as enslaved Africans to Suriname, used their ethnobotanical knowledge and native languages to name the flora in their new environment. Little is known about the influence of African languages on Saramaccan plant naming. We hypothesized that Saramaccan plant names were more influenced by Central African languages than found so far based on ethnobotanical research, because data of the Central African region was scarce. We compiled a new database on Saramaccan plant names and compared these names with an unpublished plant name database from the Democratic Republic of the Congo and the earlier published NATRAPLAND database on Afro-Surinamese plant names to find comparable plant names for botanically related species in Africa. We further analyzed form, meaning, function and categories of Saramaccan plant name components by means of dictionaries and grammars. In total, 39% of the Saramaccan plant names had an African origin, of which 44% were African retentions, 54% were innovations and 2% were misidentifications with botanical links to Africa via other plant species. Most retentions were of Central African origin (62%). The Bantu language that contributed most to Saramaccan plant names was Kikongo, followed by West African Kwa languages. Plant names reveal important information on the African origin of the Saramaccans, and deserve more scientific attention.Prevention, Population and Disease management (PrePoD)Public Health and primary car

The role of scatterometry in ocean model forcing

VI Expanding Ocean Frontiers Conference, 5-7 July 2021, Barcelona, Spain.-- 25 page

ERA*

Presentación para la ponencia Scatterometer new products en el 2nd Globcurrent User Consultation Meeting, 4-6 November 2015, Brest, France.-- 35 pagesSurface winds derived from earth Observation satellites are increasingly required for use in monitoring and forecasting of the ocean. A drawback of space-borne wind observing systems, such as scatterometers, is that they provide time and space coverage unsuitable for, among others, high-resolution ocean model forcing. As such, blended ocean forcing products combining scatterometer data and numerical weather prediction (NWP) output, are being developed over the past few years. These products, which provide full global coverage at increased temporal resolution (e.g., daily), however, generally only resolve spatial scales closer to NWP-resolved (200km) rather than scatterometer-resolved scales (25 km). Therefore, information on wind-current interaction, on the diurnal wind cycle and on wind variability in moist convection areas is lost in these blended products. Moreover, known systematic NWP model (parameterization) errors are propagated in the blended products at times and locations where no scatterometer winds are available. Direct forcing from ERA-interim or an operational global meteorological model results in even more extensive physical drawbacks, but has the advantage of increased temporal coverage. We propose to maintain this increased temporal coverage in a gridded wind and stress product, but also to maintain most beneficial physical qualities of the scatterometer winds, i.e., 25-km spatial resolution, wind-current interaction, variability due to moist convection, etc., and, at the same time avoid the large-scale NWP parameterization and dynamical errors. In fact, collocations of scatterometer and global NWP winds show these physical differences, where the local mean and variability of these differences are rather constant in time and thus could be added to the ERA-interim time record in order to better represent physical interaction processes and avoid NWP model errors. Correction of either the wind vector biases and wind vector variability is expected to affect ocean forcing. Moreover, the collocation process provides NWP winds, but sampled like a scatterometer and, therefore, provides information on the scatterometer wind sampling error. Prior to merging different scatterometer data sources, a comprehensive characterization of the scatterometer corrections is required. We provide an assessment of the corrections and sampling errors for the tandem scatterometer data set composed by ASCAT-A/B, RapidScat, Oceansat-2 and HY-2A, which, so far offer the most complementary orbits in terms of the diurnal cycle. All comparisons involve the stress-equivalent 10m wind, U10S, which avoids effects of atmospheric stratification and mass density to affect the computed wind differences. U10S may be easily computed from global NWP or moored buoy measurements for comparison to the scatterometer equivalents. U10S, in turn, can be easily related to ocean surface stressPeer Reviewe

Self-regulation of ice flow varies across the ablation area in South-West Greenland

The concept of a positive feedback between ice flow and enhanced melt rates in a warmer climate fuelled the debate regarding the temporal and spatial controls on seasonal ice acceleration. Here we combine melt, basal water pressure and ice velocity data. Using 20 years of data covering the whole ablation area, we show that there is not a strong positive correlation between annual ice velocities and melt rates. Annual velocities even slightly decreased with increasing melt. Results also indicate that melt variations are most important for velocity variations in the upper ablation zone up to the equilibrium line altitude. During the extreme melt in 2012, a large velocity response near the equilibrium line was observed, highlighting the possibility of meltwater to have an impact even high on the ice sheet. This may lead to an increase of the annual ice velocity in the region above S9 and requires further monitoring

Expression and trans-specific polymorphism of self-incompatibility RNases in Coffea (Rubiaceae)

Self-incompatibility (SI) is widespread in the angiosperms, but identifying the biochemical components of SI mechanisms has proven to be difficult in most lineages. Coffea (coffee; Rubiaceae) is a genus of old-world tropical understory trees in which the vast majority of diploid species utilize a mechanism of gametophytic self-incompatibility (GSI). The S-RNase GSI system was one of the first SI mechanisms to be biochemically characterized, and likely represents the ancestral Eudicot condition as evidenced by its functional characterization in both asterid (Solanaceae, Plantaginaceae) and rosid (Rosaceae) lineages. The S-RNase GSI mechanism employs the activity of class III RNase T2 proteins to terminate the growth of "self" pollen tubes. Here, we investigate the mechanism of Coffea GSI and specifically examine the potential for homology to S-RNase GSI by sequencing class III RNase T2 genes in populations of 14 African and Madagascan Coffea species and the closely related self-compatible species Psilanthus ebracteolatus. Phylogenetic analyses of these sequences aligned to a diverse sample of plant RNase T2 genes show that the Coffea genome contains at least three class III RNase T2 genes. Patterns of tissue-specific gene expression identify one of these RNase T2 genes as the putative Coffea S-RNase gene. We show that populations of SI Coffea are remarkably polymorphic for putative S-RNase alleles, and exhibit a persistent pattern of trans-specific polymorphism characteristic of all S-RNase genes previously isolated from GSI Eudicot lineages. We thus conclude that Coffea GSI is most likely homologous to the classic Eudicot S-RNase system, which was retained since the divergence of the Rubiaceae lineage from an ancient SI Eudicot ancestor, nearly 90 million years ago.United States National Science Foundation [0849186]; Society of Systematic Biologists; American Society of Plant Taxonomists; Duke University Graduate Schoolinfo:eu-repo/semantics/publishedVersio