ARTICLE Download: 0| View: 2| Comments: 0 | doi:10.20944/preprints201912.0106.v1
Subject: Earth Sciences, Space Science Keywords: unmanned aerial vehicle; undergraduate education; remote sensing; surveying and mapping
Online: 8 December 2019 (17:50:04 CET)
This work mainly discusses an innovative teaching platform on Unmanned Aerial Vehicle digital mapping for Remote Sensing (RS) education at Wuhan University, underlining the fast development of RS technology. Firstly, we introduce and we discuss the future development of the Virtual Simulation Experiment Teaching Platform for Unmanned Aerial Vehicle (VSETP-UAV). It includes specific topics such as the “Systems and function Design”, teaching and learning strategies, and experimental methods. This study shows that VSETP-UAV expands the usual content and training methods related to RS education, and creates a good synergy between teaching and research. The results also show that the VSETP-UAV platform is of high teaching quality producing excellent engineers, with a high international standard and innovative skill in the RS field. In particular, it develops students' practical skills with technical manipulations of dedicated hardware and software equipment (e.g., UAV) in order to assimilate quickly this particular topic. Therefore, students report that this platform is more accessible from an educational point-of-view than theoretical programs, with a quick way of learning basic concepts of RS. Finally, the proposed VSETP-UAV platform achieves high social influence, expanding the practical content and training methods of UAV based experiments, and providing a platform for cultivating high-quality national talents with internationally recognized topics related to emerging engineering education.
Sat, 7 December 2019
ARTICLE Download: 5| View: 15| Comments: 0 | doi:10.20944/preprints201912.0092.v1
Subject: Earth Sciences, Environmental Sciences Keywords: climate change; warming levels; river runoff; extremes; emission pathway; LISFLOOD; Europe; PESETA project; climate adaptation
Online: 7 December 2019 (12:22:44 CET)
The outcomes of the 2015 Paris Agreement triggered a number of climate impact assessments, such as for floods and droughts, to focus on future time frames corresponding to the years of reaching specific levels of global warming. Yet, the links between the timing of the warming levels and the corresponding greenhouse gas concentration pathways to reach them, remain poorly understood. To address this gap, we compare projected changes of annual mean, extreme high and extreme low river discharges in Europe at 1.5° and 2° under scenarios RCP8.5 and RCP4.5 from an ensemble of Regional Climate Model (RCM) simulations. The statistical significance of the difference between the two scenarios for both warming levels is then evaluated. Results show that in the majority of Europe (>95% for the annual mean discharge, >98% for high and low extremes), the changes projected in the two pathways are statistically indistinguishable. These results suggest that in studies of changes at specific warming levels the projections of the two pathways can be merged into a single ensemble without major loss of information. With regard to the uncertainty of the unified ensemble, findings show that the projected changes of annual mean, extreme high and extreme low river discharge are statistically significant in large portions of Europe.
Fri, 6 December 2019
ARTICLE Download: 4| View: 27| Comments: 0 | doi:10.20944/preprints201912.0080.v1
Subject: Earth Sciences, Environmental Sciences Keywords: bioindicator; phaseolus vulgaris; ozone pollution
Online: 6 December 2019 (11:26:57 CET)
Hong Kong is one of the most densely populated cities in the world, with millions of people exposed to severe air pollution. (1) Background: Surface ozone, mostly produced photochemically from anthropogenic precursor gases is harmful to both human and vegetation. The phytotoxicity of ozone has been shown to damage plant photosynthesis, induce early leaf death and retard growth. (2) Methods: We use genotypes of bush bean Phaseolus vulgaris with various degrees of sensitivity to ozone to investigate the impacts of ambient ozone on the morphology and development of the bean. We use ozone-induced foliar injury index and measure the flowerings and fruit production to quantify the ozone stress on the plants. (3) Results: We expected that the ozone-sensitive genotype would suffer from a reduction of yield. Results however show that the ozone-sensitive genotype suffers higher ozone-induced foliar damage as expected but produces more pods and beans and heavier beans than the ozone-resistant genotype. (4) Conclusions: It is postulated that the high ozone sensitivity of the sensitive genotype causes stress-induced flowering and therefore results in higher bean yield. A higher-than-ambient concentration of ozone is needed to negatively impact the yield production of the ozone-sensitive genotype. This study demonstrate the usefulness of bioindicators to monitor the phytotoxic effects of ozone pollution in a subtropical city such as Hong Kong.
ARTICLE Download: 9| View: 34| Comments: 0 | doi:10.20944/preprints201912.0077.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Sub-Saharan Africa; phosphorus XANES; fertilizer microdosing; African leafy vegetables; synchrotron; sustainability; nutrient stewardship
Online: 6 December 2019 (04:48:26 CET)
This study investigated the speciation, transformation and availability of P during indigenous vegetable production by employing a combination of chemical and spectroscopic techniques. The study focused upon sites in two ecozones of SSA, the Dry Savanna (lna, Benin Republic) and Rainforest (Ilesha, Nigeria). Both sites were cultivated with two indigenous vegetable species; local amaranth (Amaranthus cruentus (AV)) and African eggplant (Solanum macrocarpon (SM)). The soils were treated with 5 t/ha poultry manure and urea fertilizer at the rate of 0, 20, 40, 60 and 80 kg N/ha. Soil samples were collected before planting and after harvest. Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy was used to determine P speciation in these soils. Quantitative analysis showed that adsorbed and organic P were the two dominant P species in the manure amended Dry Savanna (DS) soils before planting and after harvest in soils cultivated with both AV and SM, with the addition of urea (40 kg N/ha) causing an increase in the organic P form in Dry Savanna soils cultivated with AV. Soils of the Rainforest (RF) cultivated with AV initially had large amounts of apatite P in the manure amended soils prior to planting which was transformed to adsorbed and organic P after harvest. Urea addition to the Rainforest soils shifted the dominant P species from organic P to adsorbed and apatite P, which is likely to limit P availability. Soils cultivated with SM had similar proportions of both organic and adsorbed P forms, with 40 kg N/ha addition slightly increased the proportion of adsorbed P.
Thu, 5 December 2019
ARTICLE Download: 4| View: 9| Comments: 1
Subject: Earth Sciences, Oceanography Keywords: 3DVAR; data assimilation; cost function; Sylvester equation
Online: 5 December 2019 (10:36:30 CET)
Three Dimensional Variational data assimilation or analysis (3DVAR) is one of most classical methods for providing the initial values for numerical models. In this method, the dimensions of the background error covariance and the observational error covariance matrices are large. Therefore, it is difficult to get the inverse of the covariance matrices and to reduce the orders of these matrices without information loss. With the use of the Sylvester Equation, on the basis of a new linear regression, a new cost function for 3DVAR was given. For the first-guess m×n field, there is an approximate 1−(m2+n2)/(mn×mn) reduction with m>1 & n>1 by using the cost function. The results of the numerical experiments show that the effect of this algorithm is no worse than that of the old cost function for 3DVAR.
Wed, 4 December 2019
ARTICLE Download: 11| View: 27| Comments: 0 | doi:10.20944/preprints201912.0047.v1
Subject: Earth Sciences, Other Keywords: SDGs; sustainable development goalsl; indicator; sustainable cities
Online: 4 December 2019 (11:16:24 CET)
United Nations Human Settlements Programme recommended equation and tools for reporting SDG indicator 11.3.1. This indicator aim at one ratio between population growth and land consumption rates in order to promote sustainable urban expansion. Because nowadays urban areas rapidly expand, with increasing rate of surface extent that over sweep the rate at which population grows. Trends.Earth was used for the key Impervious Surface Indices (30m resolution) and informed on urban trend, extent and SDG 11.3.1 of metropolitan Gombe for the periods 2000-2005, 2005-2010, and 2010-2015.The research reveals that SDG 11.3.1 for three periods stand at 0.4194, 0.4292, and 0.3041 respectively. The research also indicate that the population growth rate is greater than the land consumption.
ARTICLE Download: 16| View: 24| Comments: 0 | doi:10.20944/preprints201912.0033.v1
Subject: Earth Sciences, Atmospheric Science Keywords: convective clouds; supercell hailstorm; thunderstorm; lightning; gust; tornado, meteosat.
Online: 4 December 2019 (02:55:41 CET)
The development of extremely powerful thunderstorm which took place on August 19, 2015 is discussed in this paper. High depth hail cloud originated on the Black Sea Coast and classified as a supercell as well as several weaker hailstorms passed more than 1000 km over Northern Caucasus of Russia, the Caspian Sea, and then invaded the territory of Kazakhstan. During more than 20 hours of existence this supercell produced heavy hail, rain, intense lightning discharges, gust and tornado which rarely occurs in the region. The study of the structure and characteristics of the thunderstorm during the formation of electrical discharges and their frequency were of particular interest. According to the forecast, development of convective clouds and separate thunderstorms were expected, though the powerful hail process was not expected due to small vertical temperature gradients and the absence of cold fronts. Supercell was tracked by 5 radars located in this area, which showed its right-hand development with clock-wise deviation from the leading stream on 40-50 degrees to the right and the resulting speed of propagation was about 60-85km/h. The maximum reflectivity factor exceeded value 75dBZ, top of the clouds reached 15-16km and the height of the hail core raised on 11.2km. The size of hailstones size on most of the hail path was 2–3cm, and at the peak of cloud development - 4–5cm. Maximum frequencies of cloud-to-ground flashes of negative and positive polarities reached 30-35min-1 and 60-70min-1 correspondingly, while frequency of cloud-to-cloud flashes was significantly higher and amounted up to 300-500min-1 at the peak of the supercell development. An important fact is that the maximum frequency of flashes of different types coincided in time, showing that the reason of all discharges is similar. Total current of the cloud-to-ground flashes of positive and negative polarities was almost identical in magnitude and differed by sign. It was 200-300 kiloampere at the peak of thunderstorm development. The minimum value of radiation temperature, measured by SEVIRI radiometer installed onboard of Meteosat-10 satellite in 10.8 μm channel, was near to -60ºC. The minimum temperature value on the top of the supercell was comparable to coupled radar and sounding data. The most intensive precipitation flux derived from radiometric measurements was about 22000m3/sec; at the same period radars assessments showed precipitation up to 550mm/h (mixed phase precipitation) and size of hail 4.5cm. The combined satellite-radar-lightning data analysis showed that radar derived characteristics of the supercell reached their maximums earlier than maximum in lightning activity. The highest correlation coefficient between radar and lightning characteristics of the supercell storm was found for pair maximum reflectivity and intensity of LF (0.55) and VHF (0.66) discharges. Estimations of relationship between hail size and lightning activity showed that with increasing hail size, thunderstorm activity increases for both cloud-to-ground and intracloud flashes (on the level 0.46 - 0.59). Analysis of doppler-polarimetric data showed strong inflow zone associated with tornado. Tornadic debris signature was manifested by radar reflectivity factor ZH > 60 dBZ, differential reflectivity ZDR > -1 dB, copolar cross-correlation coefficient ρHV < 0.6, and it was collocated with the tornado vortex signature. Doppler velocities in mesocyclone zone reached values -43 and +63 m/s. Prominent radar echo hook was identified in 1.5 km layer above the ground, while ZDR columns was relatively narrow (4–8 km wide) and not very deep (4.5 km).
Tue, 3 December 2019
ARTICLE Download: 20| View: 14| Comments: 0 | doi:10.20944/preprints201912.0026.v1
Subject: Earth Sciences, Environmental Sciences Keywords: japanese larch (larix kaempferi); heterophyllous shoots; year-to-year variation; electron transport rate; nitrogen remobilization rate
Online: 3 December 2019 (11:55:45 CET)
Ground-level ozone (O3) increases in the northeastern part of Eurasia, where larch species are dominant trees and have been planted intensively. The Japanese larch (Larix kaempferi; hereafter larch) is classified as the tree species most of its sensitive to O3 based on data from long-shoot needles of seedlings. This criterion should be reconsidered based on O3 uptake, which is strongly depended on stomatal conductance (Gs) of adult trees through the difference in relevant needle traits. Because Gs is closely correlated with photosynthetic activity, we measured the in situ seasonal and yearly change in photosynthetic function, needle mass per area (LMA) and nitrogen (N) content of both short- and long-shoot needles of the canopy of larch trees over successive 3 years. No difference was observed in the in light saturated photosynthetic rate at ambient CO2 (Psat) between needles of hetero types of shoot in the latter part of the growing season, but clear differences were found within a specific year, indicating that seasonal changes in climatic factors determine Psat in the long term. The Psat-N relations differed significantly between the needle types. However, Psat at saturated CO2 (Pmax)-N was quite similar, implying that the CO2 diffusion difference between short- and long-shoots is responsible for the differing Psat -N. In conclusion, seasonal and yearly variations in photosynthetic capacity are mainly determined mainly by climatic variations, whereas shoot type determined the traits of photosynthetic N utilization as well as Gs regulation.