Abstract
Using renewable energy to drive desalination is increasingly favored to augment water supply, given its cost advantage and energy saving. Divergent renewables can be integrated into ...different desalination technologies, resulting in the selection of an appropriate renewable desalination being a challenge. This work proposes a multi-criteria decision-making framework to evaluate renewable desalination alternatives from the perspective of multi-dimensional consideration and data uncertainty by developing a mixed objective weighting (MOW) method and extending the method of MARCOS (measurement of alternatives and ranking according to a compromise solution) into uncertain conditions. Mathematical contributions can be found in the two methods, i.e. the MOW improves the objectivity and fairness in the weighting result by considering the dispersions and correlations among the criteria's performances, and interval MARCOS guarantees stability in the ranking result while well preserving the uncertain data. An illustrative case concerning four renewable desalination alternatives is used to test the feasibility of the framework. After implementing comparisons regarding the weighting result and ranking sequence, the effectiveness of the involved methods is confirmed. In conclusion, by fully utilizing objective data concerning renewable desalination while eliminating subjective interference, the developed framework can offer a rational and reliable decision output.
•We presented multi-year monthly rainfall δ18O observed at six sites in Thailand.•Winter-enriched/summer-depleted precipitation δ18O was observed for all sites.•Spatial variability of δ18O was highly ...dependent on moisture sources.•Large-scale convective activity that drive δ18O variability was investigated.
Many paleoclimatic records in Southeast Asia rely on rainfall isotope ratios as proxies for past hydroclimatic variability. However, the physical processes controlling modern rainfall isotopic behaviors in the region is poorly constrained. Here, we combined isotopic measurements at six sites across Thailand with an isotope-incorporated atmospheric circulation model (IsoGSM) and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to investigate the factors that govern the variability of precipitation isotope ratios in this region. Results show that rainfall isotope ratios are both correlated with local rainfall amount and regional outgoing longwave radiation, suggesting that rainfall isotope ratios in this region are controlled not only by local rain amount (amount effect) but also by large-scale convection. As a transition zone between the Indian monsoon and the western North Pacific monsoon, the spatial difference of observed precipitation isotope among different sites are associated with moisture source. These results highlight the importance of regional processes in determining rainfall isotope ratios in the tropics and provide constraints on the interpretation of paleo-precipitation isotope records in the context of regional climate dynamics.
Recent rapid Arctic sea-ice reduction has been well documented in observations, reconstructions and model simulations. However, the rate of sea ice loss is highly variable in both time and space. The ...western Arctic has seen the fastest sea-ice decline, with substantial interannual and decadal variability, but the underlying mechanism remains unclear. Here we demonstrate, through both observations and model simulations, that the Pacific North American (PNA) pattern is an important driver of western Arctic sea-ice variability, accounting for more than 25% of the interannual variance. Our results suggest that the recent persistent positive PNA pattern has led to increased heat and moisture fluxes from local processes and from advection of North Pacific airmasses into the western Arctic. These changes have increased lower-tropospheric temperature, humidity and downwelling longwave radiation in the western Arctic, accelerating sea-ice decline. Our results indicate that the PNA pattern is important for projections of Arctic climate changes, and that greenhouse warming and the resultant persistent positive PNA trend is likely to increase Arctic sea-ice loss.
Global mean surface air temperature (SAT) has remained relative stagnant since the late 1990s, a phenomenon known as global warming hiatus. Despite widespread concern and discussion, there is still ...an open question about whether this hiatus exists, partly due to the biases in observations. The stable isotopic composition of precipitation in mid- and high-latitude continents closely tracks change of the air temperature, providing an alternative to evaluate global warming hiatus. Here we use the long-term precipitation δ
18
O records available to investigate changes in SAT over the period 1970–2016. The results reveal slight decline in δ
18
O anomaly from 1998 to 2012, with a slope of −0.000 4‰ decade
−1
which is significantly different from that of pre-1998 interval This downward δ
18
O anomaly trend suggests a slight cooling for about −0.001 oC decade
−1
, corroborating the recent hiatus in global warming. Our work provides new evidence for recent global warming hiatus and highlights the potential of utilizing precipitation isotope for tracking climate changes.
Abstract
The spatial patterns of stable hydrogen and oxygen isotopes in precipitation (precipitation isoscapes) provide a geographic perspective to understand the atmospheric processes in modern ...environment and paleoclimate records. Here we compiled stable isotope data in modern precipitation at 223 sites across China and 48 in surrounding countries, and used regionalized fuzzy clustering to create monthly precipitation isoscapes for China (C-Isoscape). Based on regressions using spatial and climatic parameters for 12 months, the best-fitting equations were chosen for four climate clusters, and then the four layers were weighted using fuzzy membership. The moisture transportation path, controlled by the westerlies and the monsoon, results in different spatial and seasonal diversity of precipitation isotopes. Based on C-Isoscape, we determined a nationwide meteoric water line as
δ
2
H = 7.4
δ
18
O + 5.5 using least squares regression or
δ
2
H = 8.0
δ
18
O + 10.2 using precipitation weighted reduced major axis regression. Compared with previous global products, the C-Isoscape usually shows precipitation more enriched in
18
O and
2
H in summer and more depleted in winter for northwest China, while the C-Isoscape values are more enriched in heavy isotopes in most months for southwest China. The new monthly precipitation isoscapes provide an accurate and high-resolution mapping for Chinese precipitation isotopes, allowing for future intra-annual atmospheric process diagnostics using stable hydrogen and oxygen isotope in precipitation in the region.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The strontium‐to‐calcium (Sr/Ca) ratio of coral is widely used as a paleothermometer for tropical sea surface temperature (SST) at subannual resolutions. The fidelity of Sr/Ca‐derived SST estimates ...largely depends on the properties of the monthly age model selected. Here, we develop a revised monthly age model for coral Sr/Ca estimation from the northern South China Sea based on specific tie points and evaluate the impacts of different age models on SST reconstruction. Our results indicate that our revised monthly age model reduces conversion errors by up to nearly 20%–30% relative to previously reported values, thereby improving the precision of seasonal SST estimates and enabling better paleoclimate interpretations, such as El Niño–Southern Oscillation variability. The revised monthly age model provides a generalized approach for developing more robust seasonal resolution Sr/Ca–SST reconstructions in other regions.
Key Points
We develop a revised monthly age model for coral Sr/Ca‐derived sea surface temperature estimates
The new age model reduces errors by up to 20%–30% relative to previously reported
The new age model improves the accuracy of the South China Sea climate and El Niño–Southern Oscillation reconstructions
The beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), is a serious polyphagous insect pest worldwide. This species is known as a long-distance migrant, and previous studies on its ...migration have been mostly carried out in regions where it can overwinter. However, what pattern of seasonal migration this species exhibits in regions where it cannot overwinter (i.e., the 'summer breeding region') remains unknown. Here, we present data from 14-years of monitoring on a small remote island located in the center of the Bohai Strait, in northern China, by means of searchlight trapping and ovarian dissection. We found that the population size of this overseas migration varied significantly among years, with very large migrations in 2005, 2007, 2009, and 2014 that resulted in annual total catches of more than ten thousand individuals. In addition, nightly catches exhibited a significant inter-month variability, with the vast majority of S. exigua moths being trapped in August and September, (81.1 ± 3.6%), making S. exigua one of the most frequently encountered species in that period. The mean time from the earliest trap capture to the latest capture within a given year was 113 ± 22 d (range 57 d 2003 to 138 d 2008). The sex ratio (females: males) was significantly less than 1:1 in each month, but the proportion of females showed an upward trend from June to October. The majority of trapped females in summer were mated (94.4 ± 10.7% in June, 80.0 ± 6.4% in July) and sexually mature (88.9 ± 11.1% in June, 61.8 ± 12.3% in July), suggesting the onset of mating and/or sexual maturation does not terminate the migration behavior in this species. These findings provide a good starting point for study of the trans-regional migration of S. exigua across different climate zones.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Stable isotope ratios (δ18O and δD) in atmospheric precipitation and water vapor have the potential to diagnose synoptic-scale weather processes. Here we present high-frequency measurements of stable ...isotopes in water vapor and rainfall during super typhoon Lekima of 2019 in Shanghai, Eastern China. Our results indicate that both water vapor and rainfall exhibit large fluctuations in δD, with the magnitude of 94.69‰ and 57.88‰, respectively. These fluctuations reflect changes in typhoon-induced atmospheric and precipitation processes. Water vapor content and its δD values before Lekima are generally high due to stable atmospheric conditions that effectively suppress vapor condensation and isotope fractionation. During Lekima, isotope ratios in both water vapor and rainfall are complex and generally follow an inverted U-shaped pattern due to the combined effects of convection intensity, moisture convergence and rain evaporation. After Lekima, dry continental (northerly) air mass and subsidence cause a substantial decrease in both water vapor content and δD over the study region. Our study sheds light on the influence of super typhoon on isotope behaviors of water vapor and rainfall, and may have some implications for paleoclimate reconstruction of typhoon activity.
•We present a detailed isotope anatomy of super typhoon Lekima.•Both atmospheric water vapor and rainfall exhibit an inverted U-shaped pattern in response to super typhoon.•The study sheds light on processes governing water isotopes during typhoon, improving the reconstruction of paleo-typhoon.
Rapid Arctic warming and sea ice loss have led to an intensification of the Arctic hydrological cycle, which is characterized by increased local evaporation and precipitation. Stable water isotopes ...as environmental tracers can provide useful insights into the Arctic hydrological cycle. However, the paucity of isotopic observations in the Arctic has limited our understanding of the hydrological changes. Here, we use an isotope-enabled atmospheric general circulation model (IsoGSM) combined with the Global Network of Isotopes in Precipitation (GNIP) observations to investigate the relationship between sea ice changes and Arctic precipitation d18O (d18Op), and reveal the relative influence of local air temperature and evaporation on Arctic summer and winter d18Op. We find that the Arctic d18Op is negatively correlated with sea ice concentration, but positively with air temperature. Sea ice loss leads to enriched Arctic d18Op through enhanced local evaporation and warming, but the relative importance of these processes varies between seasons. During summer, both local evaporation and warming contribute equally to d18Opchanges. In contrast, winter δ18O is predominantly driven by air temperature. This work improves our understanding of how Arctic precipitation isotopes respond to sea ice changes and has implications for the Arctic hydrological cycle and paleotemperature reconstructions.
Land and sea surface temperatures, precipitation, and storm tracks in North America and the North Pacific are controlled to a large degree by atmospheric variability associated with the Pacific North ...American (PNA) pattern. The modern instrumental record indicates a trend toward a positive PNA phase in recent decades, which has led to accelerated warming and snowpack decline in northwestern North America. The brevity of the instrumental record, however, limits our understanding of long-term PNA variability and its directional or cyclic patterns. Here we develop a 937-y-long reconstruction of the winter PNA based on a network of annually resolved tree-ring proxy records across North America. The reconstruction is consistent with previous regional records in suggesting that the recent persistent positive PNA pattern is unprecedented over the past millennium, but documents patterns of decadal-scale variability that contrast with previous reconstructions. Our reconstruction shows that PNA has been strongly and consistently correlated with sea surface temperature variation, solar irradiance, and volcanic forcing over the period of record, and played a significant role in translating these forcings into decadal-to-multidecadal hydroclimate variability over North America. Climate model ensembles show limited power to predict multidecadal variation in PNA over the period of our record, raising questions about their potential to project future hydroclimatic change modulated by this circulation pattern.
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