Shortwave Components Research Articles

Comparison of methodologies for cloud cover estimation in Brazil - A case study

Clouds are the major modulator of the shortwave and longwave radiation components of the Earth's energy balance and, as such, help to regulate the planet's temperature. In the energy sector, clouds are a source of instability in the generation of energy using solar technologies. This study aims at comparing three approaches to get cloud cover information in the Southeastern region of Brazil during the period of approximately three months. The first method, assumed as reference, uses all-sky camera pictures for the cloud cover estimation. The other two methodologies use downward longwave radiation with surface meteorological data and geostationary satellite data. Both methods presented good agreement with the camera for clear sky and overcast conditions, with probabilities of detection of 92.8% and 80.7% for the longwave method and 93.3% and 87.6% for the satellite method, respectively. The major problem occurs with the broken-clouds sky scenario, with probabilities of detection above 38%, where each method has its own specificity, such as, longwave emissivity of the atmosphere, spatial resolution and view geometry. The long-wave method has the minor R correlation with the camera (87%) when compared with the satellite method (93%) and requires a daily normalization, which make it not usable for instantaneous measurements. Regarding the satellite method, the most important issue is the spatial resolution, which has the major impact on the broken-clouds sky scenarios. The cloud masking works properly for large clouds with, at least, the size comparable to the satellite image pixel. Furthermore, the method using the all-sky camera also needs to be improved, because it presented some deficiencies, like very bright areas around the sun, sometimes identified as clouds, leading to cloud cover overestimation.

Toward operational shortwave radiation modeling and retrieval over rugged terrain

Shortwave radiation (0.3–3.0μm) is a dominant component of land surface all-wave radiation budget. Reliable estimation of shortwave radiation throughout the globe is particularly important for an in-depth understanding of global changes. Unfortunately, a large number of existing space-based algorithms ignore the effects of topography by simply assuming that the surface is ideally flat. As pointed out by many studies, such neglect toward topographic effects leads to significant errors in derived radiation. This study proposes a shortwave topographic radiation model (SWTRM) by quantifying solar direct radiation shielding, occlusion of sky radiation, reflected radiation from nearby terrain, and invisibility of certain targets. To drive the SWTRM, an artificial neural network (ANN) approach was employed to generate multiple components of the shortwave radiation budget. The new model was run over the Tibetan Plateau region and used MODIS products coupled with digital elevation data (DEM). Topographically corrected shortwave fluxes were derived by coupling SWTRM and ANN outputs. The results show that: (1) the proposed SWTRM works well over mountainous regions; (2) the ANN-based shortwave model provides reasonable retrieval accuracy (RMSE <60W/m2, bias<13W/m2 for all shortwave radiation components). More importantly, the ANN model can simultaneously provide all radiation components that are indispensable for driving the SWTRM; (3) over mountainous areas, the induced error can exceed 600W/m2 for shortwave net flux. Hence, topographic effects cannot be neglected; and (4) topography and solar illumination angle are key modulators in deriving shortwave radiation from space, which control the magnitude and spatial distribution of shortwave radiation over mountainous regions.

Degradation of green InGaN-based LEDs during the tests at the constant current

The article presents the results of investigation of the degradation of electrical and optical characteristics of green InGaN-based LEDs under tests at constant direct current for 5000 hours. It is determined that LEDs which were subjected to a 4-hours exposure of high-density pulsed current degrade slowly than LEDs not exposed to this exposure. The external quantum efficiency (EQE) of the short-wave components of the radiation spectrum of the LEDs when testing reduced by a greater amount than the EQE of the long-wave components of the spectrum. For LEDs that have a current-voltage characteristic with a non-ideality factor of m≈2, the rate of decrease of optical power during testing is lower than for LEDs with m> 2.

Bright-Dark Mixed N-Soliton Solutions of the Multi-Component Mel’nikov System

By virtue of the Kadomtsev–Petviashvili (KP) hierarchy reduction technique, we construct the general bright-dark mixed N-soliton solution to the multi-component Mel’nikov system. This multi-component system comprised of multiple (say M) short-wave components and one long-wave component with all possible combinations of nonlinearities including all-positive, all-negative and mixed types. Firstly, the two-bright-one-dark (2-b-1-d) and one-bright-two-dark (1-b-2-d) mixed N-soliton solutions in short-wave components of the three-component Mel’nikov system are derived in detail. Then we extend our analysis to the M-component Mel’nikov system to obtain its general mixed N-soliton solution. The formula obtained unifies the all-bright, all-dark and bright-dark mixed N-soliton solutions. For the collision of two solitons, an asymptotic analysis shows that for an M-component Mel’nikov system with M ≥ 3, inelastic collision takes place, resulting in energy exchange among the short-wave components supporting bright s...

Analyzing the dependence of global cloud feedback on the spatial pattern of sea surface temperature change with a Green's function approach

AbstractThe spatial pattern of sea surface temperature (SST) changes has a large impact on the magnitude of cloud feedback. In this study, we seek a basic understanding of the dependence of cloud feedback on the spatial pattern of warming. Idealized experiments are carried out with an AGCM to calculate the change in global mean cloud‐induced radiation anomalies (ΔRcloud) in response to imposed surface warming/cooling in 74 individual localized oceanic “patches”. Then the cloud feedback in response to a specific warming pattern can be approximated as the superposition of global cloud feedback in response to a temperature change in each region, weighted by the magnitude of the local temperature changes. When there is a warming in the tropical subsidence or extratropical regions, the local decrease of LCC results in a positive change in Rcloud. Conversely, warming in tropical ascent regions increases the free‐tropospheric temperature throughout the tropics, thereby enhancing the inversion strength over remote regions and inducing positive global low‐cloud cover (LCC) anomalies and negative Rcloud anomalies. The Green's function approach performs reasonably well in predicting the response of global mean ΔLCC and net ΔRcloud, but poorly for shortwave and longwave components of ΔRcloud due to its ineffectiveness in predicting middle and high cloud cover changes. The approach successfully captures the change of cloud feedback in response to time‐evolving CO2‐induced warming and captures the interannual variations in ΔRcloud observed by CERES. The results highlight important nonlocal influences of SST changes on cloud feedback.

Estimating Top-of-Atmosphere Daily Reflected Shortwave Radiation Flux Over Land From MODIS Data

High-spatial resolution data of the top-of-atmosphere (TOA) reflected shortwave radiation flux are needed to understand the effects of local-scale anthropogenic and natural processes on earth’s radiation budget. A previous study developed an algorithm to estimate the TOA instantaneous shortwave component from polar-orbiting Moderate Resolution Imaging Spectroradiometer (MODIS) data. This paper presents a temporal scaling approach to predict daily values of TOA reflected shortwave radiation flux from temporally sparse MODIS observations. Radiative transfer simulation and statistical regression are used to establish the relationship between daily shortwave flux and MODIS spectral reflectance. A comparison between the Terra and Aqua combined MODIS computed data and the Clouds and the Earth’s Radiant Energy System SYN1deg product of 1° regional daily shortwave fluxes have a bias of 3.8 W/ $\text{m}^{2}$ with a root-mean-square error (RMSE) of 13.3 W/ $\text{m}^{2}$ using data from 2009 over eight subsets across various latitudes. Comparing the regional monthly shortwave fluxes reduces the RMSE to 6.9 W/ $\text{m}^{2}$ . The longer the averaging period the lower the uncertainty is self-explanatory.

Cloud and albedo enhancement impacts on solar irradiance using high-frequency measurements from thermopile and photodiode radiometers. Part 1: Impacts on global horizontal irradiance

Using many years of high-quality measurements from a variety of radiometers at both 1-min and 1-s resolution, this study provides a detailed analysis of cloud enhancement (CE) and albedo enhancement (AE) effects on solar irradiance. This first part focuses on global horizontal irradiance. Various possible definitions of the CE phenomenon are extracted from the literature and discussed, in the context of PV applications most importantly. Based on 10years of 1-min measurements of all shortwave irradiance components at a high-elevation site (1829m) on the foothills of the Rocky Mountains in Colorado, a frequency analysis of extreme events triggered by enhancement effects is carried out, using three different criteria to delineate enhancement effects: global horizontal irradiance (GHI) above 1 sun, and clearness index (KT) above either 0.8 or 1.0. This analysis shows that the annual frequency of these extreme events is extremely variable, and also largely dependent on the type of instrumentation (thermopile vs. photodiode). Although the scattering of light off cumulus-type cloud edges is directly associated with CE effects, three different types of CE phenomenon are proposed, which depend on the relative mix of diffuse and direct irradiance prior and during an episode, and on the magnitude of the regional albedo. The maximum observed global irradiance varies between 1546 and 1891Wm−2 at this site, depending on type of instrument and temporal resolution. The latter value (≈1.9 suns), obtained with a photodiode sensor at 1-s resolution, corresponds to KT=1.62 and appears to constitute a new GHI world record. It results from the combination of CE and AE effects, the latter being caused by strong backscattering, itself triggered by a fresh snow cover over the region. If the magnitude and frequency of enhancement events are critical to detect rapid transients that can be harmful to PV installations, it is suggested to rely on photodiode sensors at 1-s resolution or better.

Drivers of shortwave radiation fluxes in Arctic tundra across scales

Vegetation composition and water surface area are changing in many tundra regions due to climate warming, which is twice as strong in the Arctic as compared to the global mean. Such land cover changes feed back to climate and permafrost thaw through altering the surface energy budget. We quantified the influence of vegetation type, canopy characteristics, and patchiness on the tundra shortwave radiation components. We used in situ measurements and vegetation mapping to parametrise a 3D radiative transfer model (DART) for summer conditions at the Kytalyk test site in northeast Siberia. We analysed model results assessing the most important drivers of canopy albedo, transmittance, and absorptance of photosynthetically active radiation (PAR). Tundra albedo was strongly influenced by the fractional cover of water surfaces. Albedo decreased with increasing shrub cover. However, plant area index effects on albedo were not statistically significant. Canopy transmittance and PAR absorptance (fAPAR) were almost entirely controlled by plant area index at the landscape scale. Only about one half of the total plant area index consisted of green leaves, while wood and standing dead leaves contributed equally to the other half. While spatial patterns and patch sizes of vegetation types and open water did not significantly influence the radiation budget at the landscape scale, it contributed to the large variability at the local scale. Such local variability of shortwave radiation may impact evapotranspiration and primary productivity at a range of scales. Therefore, the variation of radiation fluxes within single vegetation types potentially affects larger scale energy, water, and carbon fluxes.

On the relative strength of radiative feedbacks under climate variability and change

Using the method of radiative ‘kernels’, an analysis is made of feedbacks in models participating in the World Climate Research Program Coupled Model Intercomparison Project phase 5. Feedbacks are calculated for RCP8.5 and abrupt4xCO2 experiments as well as for interannual and decadal variability from pre-industrial runs. Regressions across models are used to elicit relationships across experiments/timescales. Feedbacks between RCP8.5 and abrupt4xCO2 experiments show strong relationships, as expected from surface temperature response similarities arising from the two experiments. The analysis also reveals significant relationships between RCP8.5 and decadal and interannual lapse rate feedback, decadal water vapour and interannual total cloud—the latter confirming results elsewhere. To reveal the impact of warming pattern differences, ‘synthetic’ feedbacks are also generated, based on RCP8.5, whereby local feedbacks determined from that experiment are scaled by relative temperature changes (per degree of global warming) from the others. The synthetic feedbacks indicate that the (sometimes strongly) differing temperature response patterns themselves should not preclude strong correlations between variability and climate change feedbacks—indeed such correlations would be close if local feedbacks were a robust feature of the climate. Although such close correlations are not manifest, the synthetic feedbacks predict the interannual and decadal feedbacks to some extent (are correlated across models), and reveal the consistency, to a first approximation, of the mean model strength of variability feedbacks. Although cloud feedbacks at interannual timescales are correlated with those from RCP8.5, and show consistency with the strength of synthetic feedbacks, separate long and short wave components reveal very different, compensating, latitudinal patterns, suggesting the close correlation may be fortuitous.

Higher-order rogue waves with new spatial distributions for the (2 + 1) -dimensional two-component long-wave-short-wave resonance interaction system

In this paper, a two-component (2 + 1) -dimensional long-wave-short-wave (LWSW) system with nonlinearity coefficients, which describes the nonlinear resonance interaction between two short waves and a long wave, is studied. Via the Hirota's bilinear method and Pfaffian, N -order rogue waves for the LWSW system are constructed. Furthermore, correction of the N -order rogue waves is proved directly via the Pfaffian, which is cumbersome or inaccessible in other methods. Results of the first- and second-order rogue waves are presented: 1) For the first-order rogue waves, the two short-wave components are bright, while the long-wave component is dark. The position of maximum amplitude of the rogue wave is analyzed. Evolution process for the first-order rogue wave is also presented and discussed. 2) Choosing different forms of the elements defined in the Pfaffian, we obtain some kinds of the second-order rogue waves with new spatial distributions: when the elements defined in Pfaffian are the same as the first-order rogue waves, we find that the second-order rogue waves for the two short-wave components are split into two first-order rogue waves and the two bumps coexist and interact with each other; when we change the combination of the elements in Pfaffian, we find that the second-order rogue waves for the two short-wave components are split into three and four first-order rogue waves. 3) N -order rogue waves for a general M -component LWSW system are constructed.

Numerical framework and performance of the new multiple-phase cloud microphysics scheme in RegCM4.5: precipitation, cloud microphysics, and cloud radiative effects

Abstract. We implement and evaluate a new parameterization scheme for stratiform cloud microphysics and precipitation within regional climate model RegCM4. This new parameterization is based on a multiple-phase one-moment cloud microphysics scheme built upon the implicit numerical framework recently developed and implemented in the ECMWF operational forecasting model. The parameterization solves five prognostic equations for water vapour, cloud liquid water, rain, cloud ice, and snow mixing ratios. Compared to the pre-existing scheme, it allows a proper treatment of mixed-phase clouds and a more physically realistic representation of cloud microphysics and precipitation. Various fields from a 10-year long integration of RegCM4 run in tropical band mode with the new scheme are compared with their counterparts using the previous cloud scheme and are evaluated against satellite observations. In addition, an assessment using the Cloud Feedback Model Intercomparison Project (CFMIP) Observational Simulator Package (COSP) for a 1-year sub-period provides additional information for evaluating the cloud optical properties against satellite data. The new microphysics parameterization yields an improved simulation of cloud fields, and in particular it removes the overestimation of upper level cloud characteristics of the previous scheme, increasing the agreement with observations and leading to an amelioration of a long-standing problem in the RegCM system. The vertical cloud profile produced by the new scheme leads to a considerably improvement of the representation of the longwave and shortwave components of the cloud radiative forcing.

FIRST DERIVATIVE PREDICTION OF RAW BROILER SHEAR FORCE USING VISIBLE SHORT WAVE NEAR INFRARED SPECTROSCOPY

A non-destructive,fast, reliable and low cost technique which is Near-Infrared Spectroscopy (NIRS) is required to replace conventional destructive texture analyser in shear force measurement. The combination of visible and shortwave near infrared (VIS-SWNIR) spectrometer and principal component regression (PCR) to assess the quality attribute of raw broiler meat texture (shear force value (kg)) was investigated. Wavelength region of visible and shortwave 662-1005 nm was selected for prediction after pre-processing. Absorbance spectra was pre-processed using the optimal Savitzky-Golay smoothing mode with 1st order derivative, 2nd degree polynomial and 31 filter points to remove the baseline shift effect. Potential outliers were identified through externally studentised residual approach. The PCR model were trained with 90 samples in calibration and validated with 44 samples in prediction datasets. From the PCR analysis, correlation coefficient of calibration (RC), the root mean square calibration (RMSEC), correlation coefficient of prediction (RP) and the root mean square prediction (RMSEP) of visible and shortwave (662-1005 nm) with 4 principal components were 0.4645,0.0898, 0.4231 and 0.0945. The predicted results can be improved by applying the 2nd order derivative and the non-linear model.

Rogue waves for a long wave–short wave resonance model with multiple short waves

A resonance between long and short waves will occur if the phase velocity of the long wave matches the group velocity of the short wave. In this paper, a system with two distinct packets of short waves in resonance with a common long wave is studied. Breather solutions are calculated by the Hirota bilinear method, and rogue wave modes (unexpectedly large displacements from an otherwise calm background state) are obtained from the breathers through a long wave limit. The location and magnitude of the maximum displacement are determined quantitatively. Remarkably this coupling enables a rogue wave to attain a larger magnitude than that in a configuration with just one single short wave component. Furthermore, as the wavenumber varies, a transition from an elevation rogue wave to a depression rogue wave is possible. This transformation of the wave profile is elucidated in terms of the properties of the carrier envelope. The connection with the modulation instability of the background plane wave is investigated. Some numerical simulations are performed to demonstrate both the robust nature and unstable behavior for these rogue waves, depending on the parameters of the system. Dynamics and properties of rogue waves with three or more short wave components are also considered.

EXCITON RADIATION PECULIARITIES OF RED GALLIUM-PHOSPHIDE LEDS

Electroluminescence spectra of red GaP light-emitting diodes were investigated. Besides the main emission line hν = 1.845 eV, it was detected the additional short-wave component hν = 2.206 eV the existence of which is connected with donor-acceptor transitions between Zn-Sn pairs. It was observed intensity increase of this line at low currents (I 90 mA) due to the thermal effect. The nature of the spectral lines anomalous broadening was discussed.

Idealized climate change simulations with a high‐resolution physical model: HadGEM3‐GC2

AbstractIdealized climate change simulations with a new physical climate model, HadGEM3‐GC2 from The Met Office Hadley Centre are presented and contrasted with the earlier MOHC model, HadGEM2‐ES. The role of atmospheric resolution is also investigated. The Transient Climate Response (TCR) is 1.9 K/2.1 K at N216/N96 and Effective Climate Sensitivity (ECS) is 3.1 K/3.2 K at N216/N96. These are substantially lower than HadGEM2‐ES (TCR: 2.5 K; ECS: 4.6 K) arising from a combination of changes in the size of climate feedbacks. While the change in the net cloud feedback between HadGEM3 and HadGEM2 is relatively small, there is a change in sign of its longwave and a strengthening of its shortwave components. At a global scale, there is little impact of the increase in atmospheric resolution on the future climate change signal and even at a broad regional scale, many features are robust including tropical rainfall changes, however, there are some significant exceptions. For the North Atlantic and western Europe, the tripolar pattern of winter storm changes found in most CMIP5 models is little impacted by resolution but for the most intense storms, there is a larger percentage increase in number at higher resolution than at lower resolution. Arctic sea‐ice sensitivity shows a larger dependence on resolution than on atmospheric physics.

Building global and diffuse solar radiation series and assessing decadal trends in Girona (NE Iberian Peninsula)

Measurement of solar radiation was initiated in Girona, northeast of the Iberian Peninsula, in the late 1980s. Initially, two pyranometers were installed, one of them equipped with a shadowband for measuring the diffuse component. Two other pyranometers currently exist, both ventilated and one of them shadowed, with a sphere, and a pyrheliometer for measuring direct radiation. Additional instruments for other shortwave and longwave components, clouds, and atmospheric aerosols have been installed in recent years. The station is subject to daily inspection, data are saved at high temporal resolution, and instruments are periodically calibrated, all in accordance with the directions of the Baseline Surface Radiation Network. The present paper describes how the entire series of global solar radiation (1987–2014) and diffuse radiation (1994–2014) were built, including the quality control process. Appropriate corrections to the diffuse component were made when a shadowband was employed to make measurements. Analysis of the series reveals that annual mean global irradiance presents a statistically significant increase of 2.5 W m−2 (1.4 %) decade−1 (1988–2014 period), mainly due to what occurs in summer (5.6 W m−2 decade−1). These results constitute the first assessment of solar radiation trends for the northeastern region of the Iberian Peninsula and are consistent with trends observed in the regional surroundings and also by satellite platforms, in agreement with the global brightening phenomenon. Diffuse radiation has decreased at −1.3 W m−2 (−2 %) decade−1 (1994–2014 period), which is a further indication of the reduced cloudiness and/or aerosol load causing the changes.

Hall effects and sub-grid-scale modeling in magnetohydrodynamic turbulence simulations

Effects of the Hall term on short-wave components of magnetohydrodynamic turbulence and sub-grid-scale modeling of the effects are studied. Direct numerical simulations of homogeneous magnetohydrodynamic turbulence with and without the Hall term are carried out. The Hall term excites short-wave components in the magnetic field, demanding a high numerical resolution to resolve the scales smaller than the ion skin depth. A k 7 / 3 -like scaling-law in the magnetic energy spectrum associated with the excitation of the short-wave components is clearly shown by the use of both an isotropic spectrum and a one-dimensional spectrum. It is also shown that the introduction of the Hall term can cause a structural transition in the vorticity field from tubes to sheets. In order to overcome a strong demand on high-resolution in space and time and to enable quicker computations, large eddy simulations with a Smagorinsky-type sub-grid-scale model are carried out. It is shown that our large eddy simulations successfully reproduce not only the energy spectrum but also tubular vortex structures, reducing the computational cost considerably.

A grid-based model of backwasting of supraglacial ice cliffs on debris-covered glaciers

AbstractIce cliffs might be partly responsible for the high mass losses of debris-covered glaciers in the Hindu Kush-Karakoram-Himalaya region. The few existing models of cliff backwasting are point-scale models applied at few locations or assume cliffs to be planes with constant slope and aspect, a major simplification given the complex surfaces of most cliffs. We develop the first grid-based model of cliff backwasting for two cliffs on debris-covered Lirung Glacier, Nepal. The model includes an improved representation of shortwave and longwave radiation, and their interplay with the glacier topography. Shortwave radiation varies considerably across the two cliffs, mostly due to direct radiation. Diffuse radiation is the major shortwave component, as the direct component is strongly reduced by the cliffs’ aspect and slope through self-shading. Incoming longwave radiation is higher than the total incoming shortwave flux, due to radiation emitted by the surrounding terrain, which is 25% of the incoming flux. Melt is highly variable in space, suggesting that simple models provide inaccurate estimates of total melt volumes. Although only representing 0.09% of the glacier tongue area, the total melt at the two cliffs over the measurement period is 2313 and 8282 m3, 1.23% of the total melt simulated by a glacio-hydrological model for the glacier’s tongue.

Plasmon dromions in a metamaterial via plasmon-induced transparency

We propose a scheme to realize a giant Kerr nonlinearity and create stable high-dimensional nonlinear plasmon polaritons via plasmon-induced transparency (PIT) in a metamaterial, which is constructed by an array of unit cell consisting of a cut-wire and a pair of varactor-loaded split-ring resonators. We show that, due to the PIT effect and the nonlinearity contributed by the varactor, the system may possess very large second-order and third-order nonlinear susceptibilities. We further show that the system supports a resonant interaction between longwave and shortwave and hence effective third-order nonlinear susceptibility can be further enhanced one order of magnitude. Based on these peculiar properties, we derive Davey-Stewartson equations governing the evolution of longwave and shortwave envelope, and demonstrate that it possible to generate plasmon dromions [i.e., (2+1)-dimensional plasmon solitons with coupled longwave and shortwave components] with very low generation power. Our study raises the possibility for obtaining new, giant Kerr effect and stable high-dimensional nonlinear plasmon polaritons at very low radiation intensity by using nonlinear PIT metamaterials.

Experimental determination of short- and long-wave dust radiative effects in the Central Mediterranean and comparison with model results

Downward and upward irradiance measurements, in the short-wave (SW) and long-wave (LW) spectral range, have been used in combination with simultaneous aerosol optical depths (AODs) to experimentally determine the instantaneous and clear-sky aerosol Direct Radiative Forcing (DRF) at the surface, during a desert dust outbreak which affected the Central Mediterranean from 9 to 13 July 2012. AODs were retrieved from AERONET (AErosol RObotic NETwork) sun/sky photometer measurements collocated in space and time. The importance of downward and upward radiative flux measurements to properly account for both the surface albedo dependence on the solar zenith angle, and the land surface temperature (TLS) has been highlighted. Measured radiative fluxes were in reasonable agreement with the CERES (Clouds and the Earth's Radiant Energy System) and AERONET corresponding ones collocated in space and time. SW and LW downward fluxes at the surface decreased up to 9% and increased up to 13%, respectively, as a consequence of a factor 5 increase of the AOD at 675nm (AOD675). This is due to the cooling and warming effect of desert dust in the SW and LW spectral range, respectively. In fact, we have also found that the TLS increased at a rate of about 250K per unit increase of the AOD675. The aerosol DRF at the surface varied from −8 to −74Wm−2 and from +1.2 to +9.6Wm−2 in the SW and LW spectral domains, respectively. In particular, we have found that the LW-DRF on average offsets 14% of the related SW component. It is shown that a two-stream radiative transfer model can reproduce the experimental findings at the surface by replacing the refractive indices typical of dust particles with the ones obtained for a mixture made of dust and soot particles. The dust contamination by anthropogenic particles during its transport to the monitoring site located several hundred kilometers away from the source region was responsible for this last result. We have also found by model simulations that the LW-DRF increased linearly with TLS both at the surface and at the top of the atmosphere.