Surface Wetness Research Articles

STUDY ON THE ESTIMATION OF MICROWAVE LAND SURFACE EMISSIVITY OVER EAST ASIA

Estimation of the land surface emissivity is crucial to evaluate the boundary conditions of atmospheric modeling data assimilation. Brightness temperatures observed by satellite passive microwave radiometer give information on emission forma raindrops and scattering by frozen particles. By applying radiative transfer model of the atmosphere, we can estimate the atmospheric hydrological process (i. e., rainfall, snowfall, water vapor, cloud water, etc.). However it is difficult to estimate microwave land surface emissivity at higher frequencies over land. Because land use, land cover and surface wetness over land are various and heterogeneous by comparing with over ocean. Therefore, we aim to estimate the microwave land surface emissivity over East Asia by using observed data and numerical models. Firstly, we investigate the characteristics of land surface emissivity derived from SSM/I, AMSR-E and AMSR2 over Asia and the relationship between land surface emissivity and land hydrological variables based on satellite data sets and numerical models. Secondary, we estimate the land surface emissivity by applying the Community Microwave Emission Model (CMEM) and Community Radiative Transfer Model (CRTM).Simulation results shows the estimated LSE is overestimated and its variability is large by comparing the observed data.

Sand Size Affects Topdressing Removed by Mowing and Anthracnose on Annual Bluegrass Putting Green Turf

Sand size can affect the ability to incorporate topdressing into the turf canopy and thatch on golf course putting greens; unincorporated sand interferes with mowing and play. This 3-year field trial was initiated to determine the effects of sand size on sand incorporation, surface wetness, and anthracnose (caused by Colletotrichum cereale Manns sensu lato Crouch, Clarke, and Hillman) of annual bluegrass [Poa annua L. f. reptans (Hausskn) T. Koyama] maintained as a putting green. The experimental design was a randomized complete block with four replications; treatments included a non-topdressed control and three topdressing sands (medium-coarse, medium, or medium-fine) applied every 2 weeks at 0.15 L·m−2 during the summer. Topdressing with medium-coarse sand was more difficult to incorporate than the medium and medium-fine sands, resulting in a greater quantity of sand collected with mower clippings. Analyzing the particle distribution of sand removed by mowing confirmed that coarser sand particles were more likely to be removed in mower clippings. Surface wetness measured as volumetric water content (VWC) at the 0- to 38-mm depth zone was greater in non-topdressed plots than topdressed plots on 35% of observations. Few differences in VWC were found among sand size treatments. Turf responses to topdressing were not immediate; however, as sand accumulated in the turf canopy, topdressed plots typically had lower anthracnose severity than non-topdressed turf after the first year. Additionally, topdressing with medium and medium-fine sands produced similar or occasionally lower disease severity than topdressing with medium-coarse sand. The lack of negative effects of medium and medium-fine sands combined with better incorporation after topdressing and less disruption to the putting surface should allow golf course superintendents to apply topdressing at frequencies and/or quantities needed during the summer to maintain high-quality turf and playing conditions.

On the brink of Armageddon? Climate change, the archaeological record and human activity across the Bronze Age–Iron Age transition in Ireland

Palaeoclimatic proxies from records in northwest Europe evidence a climatic deterioration, known as the ‘2.8 ka Event’, which broadly coincided with the transition from Later Bronze Age to Iron Age in Ireland. This Bronze Age-Iron Age transition in Ireland has been invoked in various hypotheses concerning the relationship between environmental and cultural change. This paper offers a brief review of contrasting archaeological interpretations of the transition, outlines the gaps and uncertainties in current knowledge and highlights the role of climate change in some of these uncertainties. This is followed by a discussion of palaeoclimate records from peatlands, and in particular the utility of bog surface wetness records (BSW) to identify geographically and chronologically coherent periods of Holocene climate change, including the period around 750 BC (2.8 ka), which is apparent in both UK and Irish records. Whilst BSW records provide evidence of relative shifts from wet/cold to warm/dry conditions, quantitative indices of temperature and precipitation cannot be derived from these data. Recent work discounting a link between a demographic ‘collapse’ and climate change is considered, as is the importance of local-scale records for understanding the archaeology of peatlands. The role of ‘bog burst’ events (catastrophic hydrological failures of the physical integrity of peatland) in driving palaeohydrological changes in certain Irish peatlands is outlined. Whilst ‘bog bursts’ might confound the extraction of regional climatic meaning, they provide important contextual evidence for human activity and the associated archaeological record. Although there are some coherent patterns in palynological records, others demonstrate spatial and chronological differences in vegetation change and human impact across the Late Bronze Age to Iron Age, but the implications for changes in the distribution of human populations are unclear. The paper concludes with a consideration of the importance of robust chronologies for integrating archaeological, palaeoenvironmental and palaeoclimatological data to investigate potential links between climate and cultural change. The importance of different analytical, spatial and chronological scales to investigate the complex and recursive nature of the relationship between human activity and climatic change is discussed.

On the brink of Armageddon? Climate change, the archaeological record and human activity across the Bronze Age–Iron Age transition in Ireland

Palaeoclimatic proxies from records in northwest Europe evidence a climatic deterioration, known as the ‘2.8 ka Event’, which broadly coincided with the transition from Later Bronze Age to Iron Age in Ireland. This Bronze Age-Iron Age transition in Ireland has been invoked in various hypotheses concerning the relationship between environmental and cultural change. This paper offers a brief review of contrasting archaeological interpretations of the transition, outlines the gaps and uncertainties in current knowledge and highlights the role of climate change in some of these uncertainties. This is followed by a discussion of palaeoclimate records from peatlands, and in particular the utility of bog surface wetness records (BSW) to identify geographically and chronologically coherent periods of Holocene climate change, including the period around 750 BC (2.8 ka), which is apparent in both UK and Irish records. Whilst BSW records provide evidence of relative shifts from wet/cold to warm/dry conditions, quantitative indices of temperature and precipitation cannot be derived from these data. Recent work discounting a link between a demographic ‘collapse’ and climate change is considered, as is the importance of local-scale records for understanding the archaeology of peatlands. The role of ‘bog burst’ events (catastrophic hydrological failures of the physical integrity of peatland) in driving palaeohydrological changes in certain Irish peatlands is outlined. Whilst ‘bog bursts’ might confound the extraction of regional climatic meaning, they provide important contextual evidence for human activity and the associated archaeological record. Although there are some coherent patterns in palynological records, others demonstrate spatial and chronological differences in vegetation change and human impact across the Late Bronze Age to Iron Age, but the implications for changes in the distribution of human populations are unclear. The paper concludes with a consideration of the importance of robust chronologies for integrating archaeological, palaeoenvironmental and palaeoclimatological data to investigate potential links between climate and cultural change. The importance of different analytical, spatial and chronological scales to investigate the complex and recursive nature of the relationship between human activity and climatic change is discussed.

Climatic moisture conditions in the north-west of the Mid-Russian Upland during the Holocene

This study aimed to reconstruct the climatic moisture conditions of the Mid- Russian Upland through the Holocene. Surface moisture conditions in the study region were inferred from published pollen records from the Klukva peatland, in the north-west of the Mid-Russian Upland. Three climatic indices were derived from previously- published reconstructions of mean annual temperature and precipitation: the Climate Moisture Index, the Aridity Index and the Budyko Dryness Index. A simple modeling approach to reconstruct annual potential evapotranspiration and net radiation was developed and used to estimate the indices for different periods of the Holocene. The moisture indices were compared with independent proxies of climate moisture such as peatland surface wetness, reconstructed from testate amoebae and regional fire activity, reconstructed from charcoal. Results show that the surface moisture conditions in the study region were characterized by large variability. Periods of mild temperature and moderately wet conditions were followed by dry periods, which resulted in significant changes in palaeoenvironments. The method developed for calculation of potential evapotranspiration and indices of surface moisture conditions could be a useful tool for climate reconstructions. Our results demonstrate the detailed and nuanced palaeoclimate data which can be derived from pollen data.

From Climatic to Anthropogenic Drivers: A Multi-Proxy Reconstruction of Vegetation and Peatland Development in the French Jura Mountains

A 4 m core was extracted from the center of a peatland located in the Drugeon valley (France). Thirteen radiocarbon dates were used to build a robust age model. Testate amoebae were used for reconstructing mire surface wetness. High-resolution pollen analysis of the sequence reconstructed 9 millennia of development of the peatland and its surrounding vegetation. During the early/middle Holocene (9500 to 5800 cal BP), warm conditions led to high evapotranspiration and low water levels. The vegetation history is characterized by the development of a Pinus and a mixed Quercus forest. From 5800 cal BP, testate amoebae show wetter conditions, indicating the onset of the cooler Neoglacial period. The cooling is also evidenced by the development of Abies and Fagus trees, replacing the oak forest. The first indicators of human impact appear at about 4800 cal BP, and indicators of farming activity remains very rare until ca. 2600 cal BP, at the beginning of the Iron Age. The development of the peatland responded to climatic fluctuation until 2600 cal BP, after which human impact became the main driver. The last millennium has been characterized by sudden drying and the spread of pine on the peatland.

Wetness index based on landscape position and topography (WILT): Modifying TWI to reflect landscape position

Water and land resource management planning benefits greatly from accurate prediction and understanding of the spatial distribution of wetness. The topographic wetness index (TWI) was conceived to predict relative surface wetness, and thus hydrologic responsiveness, across a watershed based on the assumption that shallow slope-parallel flow is a major driver of the movement and distribution of soil water. The index has been extensively used in modeling of landscape characteristics responsive to wetness, and some studies have shown the TWI performs well in landscapes where interflow is a dominant process. However, groundwater flow dominates the hydrology of low-slope landscapes with high subsurface conductivities, and the TWI assumptions are not likely to perform well in such environments. For groundwater dominated systems, we propose a hybrid wetness index (Wetness Index based on Landscape position and Topography, WILT) that inversely weights the upslope contributing area by the distance to the nearest surface water feature and the depth to groundwater. When explicit depth to groundwater data are not available, height above and separation from surface water features can act as surrogates for proximity to groundwater. The resulting WILT map provides a more realistic spatial distribution of relative wetness across a low-slope Coastal Plain landscape as demonstrated by improved prediction of hydric soils, depth to groundwater, nitrogen and carbon concentrations in the A horizon of the soil profile, and sensitivity to DEM scale.

Inter-local climate zone differentiation of land surface temperatures for Management of Urban Heat in Nairobi City, Kenya

Rapid Urbanisation often leads to the formation of Urban Heat Island (UHI), which is believed to link to the characteristics of a city. Proper management of UHI, would, therefore, require recognition of the possible range of heat load increase. This paper presents results of inter-local climate zone (LCZ) differentiation of land surface temperature (LST) for the management of urban hotspots in Nairobi city. WUDAPT methodology and LST_Landsat_8_split_window toolbox were used to generate LCZ and LST maps, respectively. Nairobi LCZs had a unique thermal climate that showed statistically significant differences (< 0.05) in mean LSTs among typical LCZs. LST patterns exhibited sensitivity to building densities and heights, land cover types and surface wetness. Dry and Natural zones were more thermally responsive than wet and built-up zones. However, build-up LCZs with heavy industry, compact buildings, lightweight lowrise (slums) and large lowrise buildings were characterised with warmer LSTs while natural LCZs with water bodies, dense trees and sparsely built classes were associated with slightly lower LSTs. The findings further demonstrate and support the use of LCZs for the delimitation and investigation of the influence of complex urban morphology on local climate formation in an equatorial city like Nairobi.

Eco-Development Response to Climate Change and the Isostatic Uplift of Southwestern Finland

To date, care for our planet is mainly focused on the remediation of climate change induced by the huge amount of anthropogenic emissions of greenhouse gasses and its precursors. Transforming fossil combustion to more sustainable energy worldwide is a wellknown example. In contrast, what is little known is that the environment shaped by humans is also challenged by relatively fast geological dynamical phenomena such as the isostatic uplift of Fennoscandia, parts of Canada and northwestern Russia. Due to this uplift, the archipelago along the coast of southwestern Finland and Sweden changes rapidly to mainland. This phenomenon deeply affects both nature as well as the environment, resulting in the relocation of human activities. Here, we interpret the on-ground observed regression of the Gulf of Bothnia on the coasts of southwestern Finland and its implications on countryside activities in the framework of the eco-development paradigm. Furthermore, remotely sensed data on surface wetness confirms this sea regression and the silting-up of the nearby lakes that drain precipitation to the Gulf. We show that this eco-development paradigm may rebalance nature, environment, humans and culture and that it is a valid alternative against the past and present-day socioeconomical approach that has accelerated the change in the Earth’s climate.

Widespread drying of European peatlands in recent centuries

Climate warming and human impacts are thought to be causing peatlands to dry, potentially converting them from sinks to sources of carbon. However, it is unclear whether the hydrological status of peatlands has moved beyond their natural envelope. Here we show that European peatlands have undergone substantial, widespread drying during the last ~300 years. We analyse testate amoeba-derived hydrological reconstructions from 31 peatlands across Britain, Ireland, Scandinavia and Continental Europe to examine changes in peatland surface wetness during the last 2,000 years. We find that 60% of our study sites were drier during the period 1800–2000 CE than they have been for the last 600 years, 40% of sites were drier than they have been for 1,000 years and 24% of sites were drier than they have been for 2,000 years. This marked recent transition in the hydrology of European peatlands is concurrent with compound pressures including climatic drying, warming and direct human impacts on peatlands, although these factors vary among regions and individual sites. Our results suggest that the wetness of many European peatlands may now be moving away from natural baselines. Our findings highlight the need for effective management and restoration of European peatlands.

Modelling surface heat island intensity according to differences of biophysical characteristics: A case study of Amol city, Iran

Abstract One of the most important environmental phenomena in urban environments is urban heat island, which plays a big role in understanding anthropogenic activities. The main objective of this study is to present a novel approach based on the differences of the biophysical characteristics between built-up and non-built-up land to model Surface Heat Island Intensity (SUHII). To do so, several datasets such as Landsat images, MODIS products of MOD07L2 and MOD11A1, and data recorded at the local meteorological station for the period of 1985–2017 for Amol, Iran were used. Land Surface Temperature (LST) was calculated from single-channel algorithm and SUHII was calculated using the Surface Urban Heat Island Ratio Index (SUHIRI) as well as the surface biophysical characteristics. Finally, based on Least Squares Adjustment (LSA) model, the influence coefficient of the difference of each biophysical parameter between built-up and non-built-up land on the SUHII was calculated. The results show that the average LST of the built-up land exceeds of that for the non-built-up LST by 2.9 °C. In the study area, SUHII varies by time within 1985–2017. The standard deviation of the differences between the characteristics of brightness, greenness and surface wetness of the built-up and non-built-up land was 0.36, 0.76 and 1.17, respectively. The LSA model results show that the difference in the brightness of the built-up and non-built-up land relative to the two parameters of greenness and wetness has a greater effect on the SUHII. The coefficient of determination and root mean square error between the observed SUHII and the LSA-based calculation for the training set were 0.80 and 0.06, and for the testing set 0.75 and 0.08, respectively. The results of this study indicate the significant effect of the differences in the biophysical characteristics of land on the SUHII and the effectiveness of the model presented in the study to model the SUHII.

Bacterial survival in microscopic surface wetness.

Plant leaves constitute a huge microbial habitat of global importance. How microorganisms survive the dry daytime on leaves and avoid desiccation is not well understood. There is evidence that microscopic surface wetness in the form of thin films and micrometer-sized droplets, invisible to the naked eye, persists on leaves during daytime due to deliquescence - the absorption of water until dissolution - of hygroscopic aerosols. Here, we study how such microscopic wetness affects cell survival. We show that, on surfaces drying under moderate humidity, stable microdroplets form around bacterial aggregates due to capillary pinning and deliquescence. Notably, droplet-size increases with aggregate-size, and cell survival is higher the larger the droplet. This phenomenon was observed for 13 bacterial species, two of which - Pseudomonas fluorescens and P. putida - were studied in depth. Microdroplet formation around aggregates is likely key to bacterial survival in a variety of unsaturated microbial habitats, including leaf surfaces.

SITE SUITABILITY ANALYSIS FOR GROWING SHORT DURATION CROPS IN POST KHARIF RICE-RABI FALLOWS: AN EXPLORATORY STUDY FOR FOUR DISTRICTS OF EASTERN INDIA

Abstract. India is one of the leading rice producing countries in the world. In eastern part of the country, after harvesting of kharif rice crops, large area remains fallow, mostly due to unavailability of irrigation facility. Approximately 30 percent of total kharif rice area (i.e. around 12 Mha) is left fallow during rabi season. Government of India, in order to improve the land productivity, cropping intensity and food security, has taken up various initiatives to grow pulses in these areas. A project was launched under the National Food Security Mission for use of satellite remote sensing for suitability analysis towards crop intensification in 6 eastern Indian states. Before execution of the project an exploratory study was carried out for 4 selected districts of 2 major rice-fallow states of the country. The selected districts were Raipur and Surguja districts of Chhattisgarh state and Mayurbhanj and Balasore districts of Odisha state. Kharif rice area was mapped using RISAT-1 SAR data, while rabi fallow area was mapped using Resourcesat-2 AWiFS and Landsat-8 OLI data. Suitable area for growing pulses were analysed with respect to various soil, weather and land parameters such as, mean monthly air temperature (°C), Slope (%), Surface wetness, Plant available water capacity (mm) and proximity to drainage network. The post kharif rice-rabi fallow area, in these districts ranged between 20–40% of the geographical area, while the suitable area was found to be in range of between 8–12%. Thus, this exploratory study could show, with remote sensing and other agro-physical parameters, it is possibly not only to map the rice–fallow area, but also to assess the suitability of growing short duration rabi crops.

Videokeratoscopic assessment of silicone hydrogel contact lens wettability using a new in-vitro method

PurposeThe aim of the study was to assess the surface wettability of new-generation silicone hydrogel (SiH) contact lenses (CLs) videokeratoscopically using a new in-vitro method under office conditions. MethodVideokeratoscopic methodology was used to compare time-dependent CL wettability on an in-vitro cornea model. The model cornea was a polished chrome surface coating a Teflon form. It was prepared with a base curve of 8.7 mm and a diameter of 15 mm. Laboratory temperature and humidity were controlled. Before and after placing CLs on the on the model cornea, Bausch + Lomb Biotrue® multi-purpose solution (MPS) was dropped to simulate the pre-lens and post-lens film layer. Fanfilcon A, Senofilcon A, Samfilcon A, and Lotrafilcon B CLs with -3.00D were used, and images were taken with the videokeratoscopic method for testing. In the control group, the same procedure was performed without placing CLs. The images of CLs at 0, 60, 90, 120, 150, and 180 s were taken. Distortions and gaps seen in rings were recorded. The areas in rings were calculated in pixels using İmageJ. ResultsWhen CLs were examined, statistical differences were found among average pixel values (p < 0,001). The average pixel value was 131877.4 in the Samfilcon group, 116125.5 in the Senofilcon group, 137893.2 in the Fanfilcon group, 125578.3 in the Lotrafilcon group, and 124984.6 in the control group. No difference was found between the average values of the Lotrafilcon group and the control group. Differences were found between the average values of all other groups. DiscussionThe results obtained showed that videokeratoscopy was an effective method for in-vitro testing of CL wettability. It was found that SiH lenses displayed different performance under office conditions depending on materials and technologies used for wetting the lens surface. It was shown that lens surface wettability could be measured with a repeatable and new method when the factors affecting surface wetness and image quality were ruled out.

Non-regulatory parameters effect on consumption and emissions from a diesel-powered van over the WLTC

The effect of various non-regulatory parameters on a vehicle’s performance and emissions is investigated in this study, i.e. road grade, presence of crosswinds, surface wetness, tire pressure and use of the vehicle’s auxiliary systems. The vehicle under study is a diesel-powered turbocharged light commercial vehicle, running on the WLTC 3–2 cycle; comparison with the NEDC is also provided. The results derive from a computational code based on an engine-mapping approach applying experimentally derived correction coefficients accounting for transient operation. The engine code is coupled to a vehicle model that calculates the main longitudinal dynamic parameters (tire rolling resistance, aerodynamic performance, gearbox efficiency) on a fundamental basis. Soot and nitrogen monoxide are the examined pollutants, with fuel and energy consumption and CO2 emissions computed and discussed too. From the parameters examined, road grade was found to have the greatest impact on emissions (CO2: +116.8%, NO: +107.2%, Soot: +100.7%, for the maximum road grade examined of 8%), followed by wind speed (CO2: +38.9%, NO: +33.6%, Soot: +12%, for the maximum wind speed examined of 80 km/h). Auxiliary power demand can have a considerable effect, mostly on fuel consumption/CO2 emissions (+13.7% for maximum auxiliary power demand of 5000 W); the impact of tire inflation pressure and surface wetness is comparably smaller. Among the two driving cycles, the WLTC proved to be more ‘sensitive’ to road load changes, due to the broader speed range encompassed and its highly transient nature, compared to the softer NEDC.

COMPARISON OF AGRICULTURAL SITUATION OF INDIA FOR TWO YEARS (2017 AND 2018) USING VARIOUS DROUGHT ASSESSMENT INDICATORS DURING SOUTH WEST MONSOON SEASON IN INDIA

Abstract. Agricultural drought is concerned with the soil moisture deficiency in relation to meteorological droughts and climatic factors and their impacts on agricultural production and economic profitability. Present study is based on two years kharif seasons i.e. 2018 and 2017, comparison of drought assessment using remote sensing, soil moisture indices, rainfall and crop sown area as per the New Drought Manual, December, 2016. The drought assessment was carried out at district and sub-district level under National Agricultural Drought Assessment and Monitoring System (NADAMS) project. Drought trigger-1 is checked with rainfall deviation and dry spell. During 2017, the final drought categories were defined on the basis of Rainfall, Moisture and Vegetation Condition Index. During 2018, the final district level drought categories are defined using 3 indicators, where sown area upto end of August was also considered. Based on the approach defined in the New Drought Manual, analysis was carried out at district level for 17 major agricultural drought prone states of the country. State wise Rainfall deviation, dry spell, NDVI/NDWI situation was compared for both the years. Remote sensing based vegetation and water indices are important impact indicator out of 4 because it gives an idea of crop profile and surface wetness condition respectively. Thus the present study is an attempt to compare the drought situation in kharif season of years 2017 and 2018 on the basis of different impact indicators.

Peat humification records from Restionaceae bogs in northern New Zealand as potential indicators of Holocene precipitation, seasonality, and ENSO

In comparison with temperature reconstructions, New Zealand proxy records for paleo-precipitation are rare, despite the importance of precipitation in contemporary climate variability and for projected climate impacts. In this study, records of mid-late Holocene palaeomoisture variation were derived for two hydrologically separate ombrotrophic Restionaceae bogs in northern New Zealand, based on peat humification analysis. At each site, three cores were analysed for peat humification, facilitating both intra- and inter-site comparisons. Age models for the six sequences were developed using radiocarbon dating and tephrochronology. Twelve tephras (including six cryptotephras) were recognised, four of which were used to precisely link the two sites and to define start and end points for the records at 7027 ± 170 (Tuhua tephra) and 1718 ± 10 cal yr BP (Taupo tephra) (2σ-age ranges), respectively. We find individual differences between the six peat humification records at short-term timescales that are presumably due to local site factors, in particular changing vegetation and microtopography, or to changes in the composition of the material analysed. Stronger longer-term coherence is observed between all six records but is attributed to slow anaerobic decay over time because the implied trend towards wetter summers in the late Holocene cannot be corroborated by independent climate proxies. Despite these confounding factors, centennial scale shifts in bog surface wetness are a pervasive feature of all six records with varying degrees of overlap in time that show strong correspondence with El Niño-Southern Oscillation reconstructions from the eastern equatorial Pacific. These results indicate the potential for peat humification records from New Zealand's ombrotrophic bogs to elucidate past climate variability and also demonstrate the importance of developing multiple well-dated profiles from more than one site.

Dry and Semidry Tropical Cyclones

AbstractIt is widely believed that tropical cyclones are an intrinsically moist phenomenon, requiring evaporation and latent heat release in cumulus convection. Recent numerical modeling by Mrowiec et al., however, challenged this conventional wisdom by finding the formation of axisymmetric dry tropical cyclones in dry radiative–convective equilibrium (RCE). This paper addresses ensuing questions about the stability of dry tropical cyclones in 3D, the moist–dry vortex transition, and whether existing theories for intensity, size, and structure apply to dry cyclones. A convection-permitting model is used to simulate rotating 3D RCE, with surface wetness (0–1) and surface temperature (240–300 K) smoothly varying between dry and moist states. Tropical cyclones spontaneously form and persist for tens of days in both moist and dry/cold states, as well as part of the relatively moist/warm intermediate parameter space. As the surface is dried or cooled, cyclones weaken, both in absolute terms and relative to their potential intensities. Dry and semidry cyclones have smaller outer radii but similar-sized or larger convective centers compared to moist cyclones, consistent with existing structural theory. Strikingly, spontaneous cyclogenesis fails to occur at moderately low surface wetness values and intermediate surface temperatures of 250–270 K. Simulations with time-varying surface moisture and sea surface temperatures indicate this range of parameter space is a barrier to spontaneous genesis but not cyclone existence. Dry and semidry tropical cyclones in rotating RCE provide a compelling model system to further our understanding of real moist tropical cyclones.

RETRACTED ARTICLE: Assessing the influence of highway and high-speed railway construction on local climate using Landsat images in karst areas

Large-scale transportation infrastructure construction in ecologically vulnerable areas such as the karst region of Southwest China requires estimation method for better project design. This research was carried out on a four-lane highway (the Guilin-Guiyang highway, G76) and a two-lane high-speed railway (the Guilin-Guiyang high-speed railway, GGHSR) in karst areas in Guizhou and Guangxi provinces. The highway and high-speed railway were constructed in the 2010s and covered by Landsat images whose multispectral information could be used for research purposes. In this study, the severity of the impact and the CO2 emissions from the G76 and GGHSR construction were evaluated. Landsat images and field meteorological measurements were applied to calculate the surface functional parameters (surface temperature and surface wetness) and heat fluxes (latent, sensible and ground heat flux) before and during the highway and high-speed railway construction; the amount of CO2 emissions during the G76 and GGHSR construction were determined by using budget sheets, which record the detail consumptions of materials and energy. The results showed that the decrease of water evaporation from the highway and high-speed railway construction can reach up to 26.4 m3 and 20.1 m3 per kilometer, which corresponds to an average decrease in the vegetation cooling effect of 18.0 MWh per day per highway kilometer and 13.7 MWh per day per high-speed railway kilometer, respectively. At the meantime, the average CO2 emission densities from the G76 and GGHSR construction can reach up to 24813.7 and 36921.1 t/km, respectively. This study implied that extensive line constructions have a significant impact on the local climate and the energy balance, and it is evident that selecting and planting appropriate plant species can compensate for the adverse effects of line constructions in karst mountain regions.

Multicomponent Satellite Assessment of Drought Severity in the Contiguous United States From 2002 to 2017 Using AMSR‐E and AMSR2

AbstractThe Advanced Microwave Scanning Radiometer for the Earth Observing System and Advanced Microwave Scanning Radiometer 2 sensors (AMSR) have provided multifrequency microwave measurements of the global terrestrial water cycle since 2002. A new AMSR surface wetness index (ASWI) was developed by analyzing the near‐surface atmospheric vapor pressure deficit (VPD), surface volumetric soil moisture (VSM), and land surface fractional open water (FW) time series from an established AMSR Land Parameter Data Record (LPDR). The ASWI allows for multicomponent and independent satellite assessments of near‐surface drought conditions by exploiting the weighted anomalies of VPD, VSM, and FW. Comparisons between ASWI and more traditional drought metrics, including the Palmer moisture anomaly index (PDSI‐Z) and the U.S. Drought Monitor, showed generally consistent classifications of drought severity for three major droughts over the Contiguous United States since 2002. The AWSI showed moderate (0.3 ≤ R ≤ 0.7 for 56% of area) to strong (R &gt; 0.7 for 29% of area) correlations with the PDSI‐Z during the summer months (June–August) from 2002 to 2017. ASWI and PDSI‐Z differences were attributed to AMSR retrieval uncertainties and the different aspects of drought represented by the indices. Comparisons between ASWI and the Gravity Recovery and Climate Experiment drought severity index (GRACE‐DSI) showed strong correspondence (R = 0.61) in regions where possible long‐term total water storage changes occurred. The sole reliance of the ASWI on satellite microwave remote sensing and continuing AMSR2 operations enables effective global monitoring of drought conditions while providing new information on the atmosphere, soil, and surface water components of drought.