Improved Bi-Angle Aerosol Optical Depth Retrieval Algorithm from AHI Data Based on Particle Swarm Optimization

The Advanced Himawari Imager (AHI) aboard the Himawari-8, a new generation of geostationary meteorological satellite, has high-frequency observation, which allows it to effectively capture atmospheric variations. In this paper, we have proposed an Improved Bi-angle Aerosol optical depth (AOD) retrieval Algorithm (IBAA) from AHI data. The algorithm ignores the aerosol effect at 2.3 μm and assumes that the aerosol optical depth does not change within one hour. According to the property that the reflectivity ratio K of two observations at 2.3 μm does not change with wavelength, we constructed the equation for two observations of AHI 0.47 μm band. Then Particle Swarm Optimization (PSO) was used to solve the nonlinear equation. The algorithm was applied to the AHI observations over the Chinese mainland (80°–135°E, 15°–60°N) between April and June 2019 and hourly AOD at 0.47 μm was retrieved. We validated IBAA AOD against the Aerosol Robotic Network (AERONET) sites observation, including surrounding regions as well as the Chinese mainland, and compared it with the AHI L3 V030 hourly AOD product. Validation with AERONET of 2079 matching points shows a correlation coefficient R = 0.82, root-mean-square error RMSE = 0.27, and more than 62% AOD retrieval results within the expected error of ±(0.05 + 0.2 × AODAERONET). Although IBAA does not perform very well in the case of coarse-particle aerosols, the comparison and validation demonstrate it can estimate AHI AOD with good accuracy and wide coverage over land on the whole.

STUDY THE BIOPOTENTIAL PARAMETER FOR DETECTION OF SEISMIC AND ENVIORNMENTAL CHANGES IN INDIAN REGION

The changes in the magnetic flux generated (electric, magnetic and electromagnetic waves) on the surface of earth due to sudden changes is a matter of discussion. These emissions occur along the fault line generated due to geological and tectonic processes. When sudden changes occur in the environment due to seismic and atmospheric variations, these sensing was observed by creatures and human bodies because the animals and trees adopt the abnormal signals and change the behavior. We have analyzed the changing behavior of recorded signal by live sensors (i.e. banyan tree). So we use the deep rooted and long age’s banyan tree. Banyan tree (long ages) in which root has been working as a live sensor and record the geological and environmental changes. We record the low frequency signals which propagated through solar-terrestrial environment affect directly the root system of the banyan tree and changes has been observed by live sensors. Then, VLF signal ma(y propagate to the earth-ionosphere waveguide. We have also analyzed the different parameters of live cells which is inbuilt in latex of the tree, so we record the dielectric parameters of green stem latex and found some parameters i.e., dielectric constant (ε) and dielectric loss (ε’) of various trees to verify these natural hazards and found good correlation. Therefore, we can say by regularly monitoring the bio-potential signal and dielectric properties of banyan tree we can able to find the precursory signature of seismic hazards and environmental changes.

Study the bio-potential parameter for the detection of seismic and environmental changes in Indian region

The changes the magnetic flux generated (electric, magnetic and electromagnetic waves) on the surface of earth due to sudden changes is a matter of discussion. These emissions occur along the fault line generated due to geological and tectonic processes. When sudden changes occur in the environment due to seismic and atmospheric variations, these sensing was observed by creatures and human bodies because the animals and trees adopt the abnormal signals and change the behavior. We have analyzed the changing behavior of recorded signal by live sensors (i.e., banyan tree). So we use the deep-rooted and long-aged banyan tree. The root of banyan tree (long-aged) has been working as a live sensor to record the geological and environmental changes. We record the low frequency signals propagated through solar-terrestrial environment which directly affect the root system of the banyan tree and changes that have been observed by live sensors. Then, very low frequency (VLF) signal may propagate to the earth-ionosphere waveguide. We have also analyzed the different parameters of live cells which is inbuilt in latex of the tree, so we record the dielectric parameters of green stem latex and found some parameters i.e., dielectric constant (ε) and dielectric loss (ε’) of various trees to verify these natural hazards and found good correlation. Therefore, we can say by regularly monitoring the bio-potential signal and dielectric properties of banyan tree and we are able to find the precursory signature of seismic hazards and environmental changes.

Are Opening Angles in Exoplanet Transmission Spectroscopy Overestimated?

<p>Transmission spectroscopy has been integral to the atmospheric characterisation of transiting exoplanets – constraining their chemical abundances and temperature profiles. However, transit spectra are often interpreted using 1D models of the atmosphere, and this can lead to biased inferences in retrievals. Especially on tidally locked planets, which have a permanently irradiated dayside and a permanently dark nightside, atmospheric variations along the line of sight can be substantial. In order to assess whether a 1D model suffices, or whether a 3D model is needed to interpret observational data, one requires an estimate of the planet’s opening angle. This is the angle subtended by the atmospheric region that contributes to the observation along the line of sight, as seen from the centre of the planet. In this talk, we show that the opening angles that have been computed in previous works are likely an overestimation of the true opening angles. This is because the maximum and minimum pressure probed by transit observations do not lie on the same transit chords. Using two different methods, we re-evaluate the opening angles for a large number of atmospheres with different scale heights and planetary radii. We also present a new analytical formula to estimate the more realistic size of the opening angle.</p>

Annual and seasonal glaciological mass balance of Patsio Glacier, western Himalaya (India) from 2010 to 2017

Improving the knowledge on Himalayan glaciers mass balance is a key to understand the present and past annual atmospheric variations and future water availability in the region. Here, we present glaciological mass balance for Patsio Glacier, located in Himachal Pradesh (India), western Himalaya. Annual glacier-wide mass balance was measured for 7 consecutive years (2010/11 to 2016/17) and winter mass balance for 6 years (2011/12 to 2016/17). The cumulative mass balance over this period was −2.35 ± 0.37 m w.e. The corresponding mean mass balance was −0.34 m w.e. a−1. The mean annual ablation gradient excluding the debris-covered area was 0.47 m w.e. (100 m)−1. The annual ablation over the debris-covered area is reduced by an average of −1.0 m w.e. compared to the clean ice surface. Winter mass balance was consistently positive with a maximum of 1.34 m w.e. in 2014/15 and a minimum of 0.88 m w.e. in 2011/12. Multiple regression analysis between annual mass balance versus annual and winter precipitation of the Lahaul-Spiti region shows a significant positive correlation. Our results highlight the importance of monitoring seasonal mass balance and consideration of non-climatic parameters (debris and aspect) while estimating the glacier-wide mass balance.

CMIP5 climate projections and RUSLE-based soil erosion assessment in the central part of Iran

Soil erosion (SE) and climate change are closely related to environmental challenges that influence human wellbeing. However, the potential impacts of both processes in semi-arid areas are difficult to be predicted because of atmospheric variations and non-sustainable land use management. Thus, models can be employed to estimate the potential effects of different climatic scenarios on environmental and human interactions. In this research, we present a novel study where changes in soil erosion by water in the central part of Iran under current and future climate scenarios are analyzed using the Climate Model Intercomparison Project-5 (CMIP5) under three Representative Concentration Pathway-RCP 2.6, 4.5 and 8.5 scenarios. Results showed that the estimated annual rate of SE in the study area in 2005, 2010, 2015 and 2019 averaged approximately 12.8 t ha−1 y−1. The rangeland areas registered the highest soil erosion values, especially in RCP2.6 and RCP8.5 for 2070 with overall values of 4.25 t ha−1 y−1 and 4.1 t ha−1 y−1, respectively. They were followed by agriculture fields with 1.31 t ha−1 y−1 and 1.33 t ha−1 y−1. The lowest results were located in the residential areas with 0.61 t ha−1 y−1 and 0.63 t ha−1 y−1 in RCP2.6 and RCP8.5 for 2070, respectively. In contrast, RCP4.5 showed that the total soil erosion could experience a decrease in rangelands by − 0.24 t ha−1 y−1 (2050), and − 0.18 t ha−1 y−1 (2070) or a slight increase in the other land uses. We conclude that this study provides new insights for policymakers and stakeholders to develop appropriate strategies to achieve sustainable land resources planning in semi-arid areas that could be affected by future and unforeseen climate change scenarios.

On the relationship between stable isotopes and major impurity species as inferred from a two-dimensional firn sampling approach at EDML, East Antarctica

<p>Ice cores constitute a major palaeoclimate archive by recording, among many others, the atmospheric variations of stable oxygen and hydrogen isotopic composition of water and of soluble ionic impurities. While impurities are used as proxies for, e.g., variations in sea ice, marine biological activity and volcanism, stable isotope records are the main source of information for the reconstruction of polar temperature changes.</p><p>However, such reconstruction efforts are complicated by the fact that temperature is by far not the only driver of isotopic composition changes. A single isotopic ice-core record will comprise variations caused by a multitude of processes, from variable atmospheric circulation and moisture pathways to the intermittency of precipitation and finally to the mixing and re-location of surface snow by wind drift (stratigraphic noise). Under the assumption that specific trace components are originally deposited with the precipitated snow and its isotopic composition, the retrieved impurity records should display a similar spatial and seasonal to interannual variability as the isotope records, caused by local stratigraphic noise as well as the time-variable and intermittent precipitation patterns, respectively.</p><p>In this contribution, we investigate the possible relationship between isotope and impurity data at the East Antarctic low-accumulation site EDML. We sampled and analysed isotopic composition and major impurity species on a four metre deep and 50 metre long trench. This enables us (1) to study the spatial (horizontal times vertical) relationship in the data, and (2) to analyse and compare the seasonal and interannual variability after removing the strong contribution of local stratigraphic noise. By this, the study improves our understanding of the depositional mechanisms that play an important role for the formation of ice-core records, and it offers to investigate the potential of using impurities to correct isotopic variability in order to improve temperature reconstructions.</p>

Análise do conteúdo de umidade foliar de fitofisionomias do Cerrado com uso de imagens do multispectral instrument do satélite Sentinel 2

O estudo realizou uma análise comparativa entre o índice de reflectância de duas fitofisionomias (Macega e Cerradão) do Cerrado nas bandas de imagens do Instrumento Multiespectral (MSI) do satélite Sentinel 2 das bandas Short-wave infrared (SWIR) 1 e 2 e Near Infra-Red (NIR) de duas fitofisionomias do Cerrado em consonância com os dados in situ de Fuel Moisture Content (FMC) afim de contribuir com técnicas de Sensoriamento Remoto para monitorar combustíveis vegetais e perigos de incêndio. Dados adicionais de variáveis ambientais como temperatura e umidade do ar, e de satélites como precipitação e conteúdo de umidade de solo foram consideradas neste estudo. A análise dos dados foi feita com a aplicação de correlação linear e de regressão múltipla. No FMC, os resultados ficaram acima de 100% para o Cerradão e para a Macega atingiu valor mínimo de 20%. Na análise de correlação, a banda NIR se correlacionou positivamente (R² = 0,32) ao FMC do Cerradão, enquanto na Macega, a melhor correlação foi identificada nas bandas do SWIRs (R² = 0,36) inversamente ao FMC. Na análise de regressão, o FMC do Cerradão indicou correspondência à umidade de solo. Conclui-se que vegetais vivos tendem a recorrer a umidade do solo, enquanto que os vegetais mortos são mais afetados por variáveis atmosféricas e, por isso, são mais propensos a incêndios, como a Macega. O monitoramento do FMC por Sensoriamento Remoto requer maior amostragem em relação ao bioma Cerrado, cuja fisiologia complexa mostra ser influenciada por variáveis ambientais e climáticas que deverão ser levadas em conta em análises e estudos posteriores. Leaf moisture content analysis of Cerrado phytophysiognomies using Sentinel 2 satellite multispectral instrument images A B S T R A C T Moisture content of living or dead plant material is a fundamental element in the characterization of the fire's fuel load in wildfire episodes. Satellite imagery and field surveys can help to estimate Fuel Moisture Content (FMC) in different environments. FMC is computed as wet weight over dry weight of vegetation samples. In this study, 24 FMC samples of Brazilian Savana vegetation were collected between May and October 2019 in two phytotypes: Cerrado Típico and Campo Limpo, in the municipality of Sacramento / MG. We applied an statistic correlation to reflectance of the Sentinel-2 MSI spectral bands (Multispectral Instrument). Data on soil moisture, temperature, precipitation and air humidity were tested in a Multiple Linear Regression to verify possible impacts of these elements on FMC results. SWIR 1 band had a better correlation (R² = 0.33) with Campo Limpo samples, the reflectance increases as the plant's humidity decreases, turning to dead leaves. In Cerrado Típico, FMC increased during the period, keeping leaves alive. Dead leaves are affected by atmospheric variations and are more prone to burning. The risk of fire is imminent in Campo Limpo and reflectance analysis of short wave infrared (SWIR) is a strategy to predict risk of fires in this environment.Keywords: wildfire risk; fuel moisture content; reflectance

Atmosphere–Ocean Interactions and Their Footprint on Heat Transport Variability in the Northern Hemisphere

Interactions between the atmosphere and ocean play a crucial role in redistributing energy, thereby maintaining the energy balance of the climate system. Here, we examine the compensation between the atmosphere and ocean’s heat transport variations. Motivated by previous studies with mostly numerical climate models, this so-called Bjerknes compensation is studied using reanalysis datasets. We find that atmospheric energy transport (AMET) and oceanic energy transport (OMET) variability generally agree well among the reanalysis datasets. With multiple reanalysis products, we show that Bjerknes compensation is present at almost all latitudes from 40° to 70°N in the Northern Hemisphere from interannual to decadal time scales. The compensation rates peak at different latitudes across different time scales, but they are always located in the subtropical and subpolar regions. Unlike some experiments with numerical climate models, which attribute the compensation to the variation of transient eddy transports in response to the changes of OMET at multidecadal time scales, we find that the response of mean flow to the OMET variability leads to the Bjerknes compensation, and thus the shift of the Ferrel cell at midlatitudes at decadal time scales in winter. This cell itself is driven by the eddy momentum flux. The oceanic response to AMET variations is primarily wind driven. In summer, there is hardly any compensation and the proposed mechanism is not applicable. Given the short historical records, we cannot determine whether the ocean drives the atmospheric variations or the reverse.