Scaling property of regional floods in New South Wales Australia

Regional flood frequency analysis (RFFA) is often used in hydrology to estimate flood quantiles when there is a limitation of at-site recorded flood data. One of the commonly used RFFA methods is the index flood method, which is based on the assumptions that a region satisfies criterion of simple scaling and it can be treated homogeneous. Another RFFA method is quantile regression technique where prediction equations are developed for flood quantiles of interest as function of catchment characteristics. In this paper, the scaling property of regional floods in New South Wales (NSW) State in Australia is investigated. The results indicate that the annual maximum floods in NSW satisfy a simple scaling assumption. The application of a heterogeneity test, however, reveals that NSW flood data set does not satisfy the criteria for a homogeneous region. Finally, a set of prediction equations are developed for NSW using quantile regression technique; an independent test shows that these equations can provide reasonably accurate design flood estimates with a median relative error of about 27%.     

Channel morphology and river flow in the northern Russian Plain in the Late Glacial and Holocene

The relicts of large meandering palaeochannels are found throughout the territory of the periglacial zone of the Last (Valdai=Weichselian) Glaciation on the Russian Plain. Channel widths of macromeanders can be 15 times larger than the recent meanders of the same rivers. Palaeolandscape and palaeohydrological reconstructions show that these periglacial river channels were formed under conditions of high spring water flow, up to eight times greater than the modern discharges, when the flow coefficient was close to 0.9-1.0 due to presence of permafrost, summers were dry and streams lacked ground water supply. Permafrost degradation increased soil permeability in spring and increased ground water flow in summer, causing a decrease of annual flow (due mainly to the flood flow decrease in spring). As a result, large periglacial channels were abandoned and transformed into lakes and bogs. Late Holocene channels have much smaller channel widths and meander lengths. These were formed under conditions of lower annual flows and much steadier flow regime.     

The two micron all sky survey

This paper describes the design, expectations, and prototyping of a new allsky survey, called 2MASS (Two Micron All Sky Survey) to be carried out with the new generation of infrared array detectors.     

Africa and the Green Climate Fund: current challenges and future opportunities

Although the Green Climate Fund (GCF) is widely commendable in several ways, access to the Fund has been very challenging for many African countries. Using GCF published statistics, we identify possible challenges likely to be responsible for this. First, we present an assessment of the GCF’s Readiness Support Programme with respect to how the programme’s performance may have affected achievement of African countries’ readiness outcomes. Second, a critical evaluation of the status of African GCF portfolio (pipeline and approved projects) provides a means by which to assess how well Africa’s current portfolio aligns with GCF strategic impact areas, results areas and investment priorities. We then discuss GCF access modalities and the implications of relying on International Accredited Entities (IAEs) to indirectly access the Fund. The readiness support assessment indicates that the distribution of support requests and funding approvals is nearly equal across the regions of Africa, Asia Pacific and Latin America and the Caribbean. However, when the regions are considered individually, Africa demonstrates lower approvals with respect to requests and securing funding. Results from the GCF portfolio evaluation reveal that little or no attention has been devoted to GCF critical result areas such as forests and land use or transport, where great potentials for low-carbon development transitions exist. With respect to access modalities, the IAE financing mechanism currently provides access to the Fund for the majority of projects in both the global and African GCF portfolios. The implications of these findings are extensively discussed.

Key policy insights

• For Africa, limited readiness support and a reliance on International Accredited Entities constrains capacity building, thereby reinforcing a lack of both readiness and direct access to the GCF.

• There are opportunities for Africa to diversify its GCF portfolios, adhere to international commitments, and address its adaptation and development needs by identifying and capitalizing on linkages between GCF funding priorities, mitigation, and adaptation.

• There are leverage points within existing climate finance and governance systems that could catalyse a shift in Africa’s engagement with the GCF and generate positive, cascading effects on institutional strengthening, direct access accreditation and securing funding.

     

Sesquiterpenoids in sediments of a hypersaline lagoon: A possible algal origin

Core samples were collected in Lagoa Vermelha, a hypersaline lagoon located about 100 km east of Rio de Janeiro (Brazil). The sediment composition is predominantly carbonate in amounts up to 93%. Analysis of δ¹³C of the total organic matter in the sediments showed that marine organic matter predominates throughout the core (δ¹³C ranges from −15.84 to −22.64‰ vs. PDB). Organic carbon contents (TOC) ranged from 0.81 to 13.28%. A series of cadinane-type sesquiterpenoids can be recognized in the gas chromatography-mass spectrometry data. Essentially the same components are present in all the samples, with variations only in their relative abundances. The most abundant compounds are α- and β-cubebene, α- and β-cedrene, cadinenes (different isomers), α-curcumene and calamenene, with minor amounts of calarene, humulene, calacorene and cadalene. Since this lagoon is surrounded by dunes with only minor vegetation typical of this environment (grasses, small non-resinous shrubs and no forest) with no potential source for sesquiterpenoids, a terrestrial origin for these compounds is excluded and an algal origin is more consistent with the locale and the recognition of sesquiterpenoids (including cadinol) in microbial mats from the lagoon. Only the natural product precursor sesquiterpenoids are present in the microbial mats with no detectable diagenetic derivatives (e.g. calamenene and cadalene). This indicates that the compounds in the mats are from recent input and those found in the sediments are most likely derived from former algal biomass in this lagoon, a fact confirmed by the recognition of a series of diagenetic aromatic components in the sediments. Surface sediments contain n-alkanes with no even-to-odd predominance indicating that microbial activity is higher in shallower sediments. Moreover, mass fragmentograms (m/z 191) of biomarkers revealed the presence of 17α(H),21β(H)-hopanes, the mature isomers, together with their ββ precursors and low amounts of the intermediates with the βα configuration (moretanes). This indicates a contribution of mature organic matter to these immature sediments.     

Florida Bay: Modern analogue for Lofer cyclothems?

Lofer cyclothems of the Alpine Upper Triassic have many features in common with Holocene sediments of Florida Bay. The modal ‘complete’ Lofer cycle is essentially symmetrical, having a deepening and shoaling phase, as does the cycle-in-progress in Florida Bay. Lateral discontinuity and thickness variations within members of the Lofer cyclothems indicate syn-depositional relief, possibly in the form of mud banks, the signature feature of Florida Bay sedimentation. Spatial and temporal dimensions, although poorly constrained, appear comparable. Analogous depositional textures, biota and sedimentary structures, while not unique to either environment, strengthen the inferences that can be made about the Triassic depositional environment and regarding future evolution of the modern environment. The striking similarities between the Holocene icehouse sediments and the Late Triassic greenhouse deposits suggest that sedimentation patterns at the scale of individual cycles or parasequences may be largely independent of the global climate regime.     

North American transect of stable hydrogen and oxygen isotopes in water beetles from a museum collection

Museum collections contain a wealth of insect remains originating from a wide geographic range, which can be used to investigate their utility as a proxy for environmental isotope ratios. Chitinous remains of insects such as beetles (Coleoptera) are chemically stable and their stable isotope composition is strongly related to that of environmental water in the period of cuticle formation. We present a dataset of chitin ??D and ??¹⁸O in two genera of water beetles from a museum collection containing 40 locations for Helophorus (water scavenging beetles) and 48 locations for Hydroporus (predaceous diving beetles) that were selected from latitudes 27?C82°N in North America. Only two genera were used to minimize inter-sample variation caused by species-specific differences in metabolic effects, feeding strategy, habitat, and life cycle. The isotopic composition of water beetle exoskeletons had a strong latitudinal trend (North?CSouth) from ?160 to +65??? for ??D and from 7 to 34??? for ??¹⁸O, paralleling gradients of isotopes in precipitation. Strong relationships were observed between isotopic composition of beetles and modelled July precipitation (0.71?<?R ²?<?0.82, p?<?0.001). The relationship between ??D and ??¹⁸O in the beetle samples had a systematic offset from the global meteoric water line, which was likely caused by metabolic effects during chitin formation. The offset between ??D values in beetles and in modelled precipitation was 33??? larger, on average, for Hydroporus compared with Helophorus, suggesting fractionation of hydrogen isotopes during passage through the food chain. This trophic level effect was not observed for stable oxygen isotopes. Furthermore, the observed deviations between isotopic composition of water beetles and modelled precipitation at collection sites were not constant and indicated local hydrological deviations from modelled precipitation. The largest deviations were observed for sites in the Southern US and the Arctic that are highly evaporative and at sites in the Rocky Mountains and Coastal Mountains that were fed by snow melt. Our results indicated that the isotopic composition of water beetles from a museum collection was systematically related to ??D and ??¹⁸O values of precipitation at the collection site.