scholarly journals The Austrian radiation monitoring network ARAD – best practice and added value

2016 ◽  
Vol 9 (4) ◽  
pp. 1513-1531 ◽  
Author(s):  
Marc Olefs ◽  
Dietmar J. Baumgartner ◽  
Friedrich Obleitner ◽  
Christoph Bichler ◽  
Ulrich Foelsche ◽  
...  
Keyword(s):  
Quality Control ◽  
Global Radiation ◽  
National Level ◽  
Monitoring Network ◽  
Diffuse Radiation ◽  
Atmospheric Modeling ◽  
Radiation Monitoring ◽  
Surface Radiation ◽  
Added Value ◽  
Accuracy Of Measurements

Abstract. The Austrian RADiation monitoring network (ARAD) has been established to advance the national climate monitoring and to support satellite retrieval, atmospheric modeling and the development of solar energy techniques. Measurements cover the downward solar and thermal infrared radiation using instruments according to Baseline Surface Radiation Network (BSRN) standards. A unique feature of ARAD is its vertical dimension of five stations, covering an altitude range between about 200 m a.s.l (Vienna) and 3100 m a.s.l. (BSRN site Sonnblick). The paper outlines the aims and scopes of ARAD, its measurement and calibration standards, methods, strategies and station locations. ARAD network operation uses innovative data processing for quality assurance and quality control, utilizing manual and automated control algorithms. A combined uncertainty estimate for the broadband shortwave radiation fluxes at all five ARAD stations, using the methodology specified by the Guide to the Expression of Uncertainty in Measurement indicates that relative accuracies range from 1.5 to 2.9 % for large signals (global, direct: 1000 W m−2, diffuse: 500 W m−2) and from 1.7 to 23 % (or 0.9 to 11.5 W m−2) for small signals (50 W m−2) (expanded uncertainties corresponding to the 95 % confidence level). If the directional response error of the pyranometers and the temperature response of the instruments and the data acquisition system (DAQ) are corrected, this expanded uncertainty reduces to 1.4 to 2.8 % for large signals and to 1.7 to 5.2 % (or 0.9–2.6 W m−2) for small signals. Thus, for large signals of global and diffuse radiation, BSRN target accuracies are met or nearly met (missed by less than 0.2 percentage points, pps) for 70 % of the ARAD measurements after this correction. For small signals of direct radiation, BSRN targets are achieved at two sites and nearly met (also missed by less than 0.2 pps) at the other sites. For small signals of global and diffuse radiation, targets are achieved at all stations. Additional accuracy gains can be achieved in the future through additional measurements, corrections and a further upgrade of the DAQ. However, to improve the accuracy of measurements of direct solar radiation, improved instrument accuracy is needed. ARAD could serve as a useful example for establishing state-of-the-art radiation monitoring at the national level with a multiple-purpose approach. Instrumentation, guidelines and tools (such as the data quality control) developed within ARAD are intended to increase monitoring capabilities of global radiation and thus designed to allow straightforward adoption in other regions, without high development costs.

scholarly journals The Austrian radiation monitoring network ARAD – best practice and added value

2015 ◽  
Vol 8 (10) ◽  
pp. 10663-10710 ◽  
Author(s):  
M. Olefs ◽  
D. J. Baumgartner ◽  
F. Obleitner ◽  
C. Bichler ◽  
U. Foelsche ◽  
...  
Keyword(s):  
Quality Control ◽  
Best Practice ◽  
National Level ◽  
Temperature Response ◽  
Monitoring Network ◽  
Radiation Monitoring ◽  
Surface Radiation ◽  
Added Value ◽  
Shortwave Radiation ◽  
Data Quality Control

Abstract. The Austrian RADiation monitoring network (ARAD) has been established to advance the national climate monitoring and to support satellite retrieval, atmospheric modelling and solar energy techniques development. Measurements cover the downwelling solar and thermal infrared radiation using instruments according to Baseline Surface Radiation Network (BSRN) standards. A unique feature of ARAD is its vertical dimension of five stations, covering an air column between about 200 m a.s.l. (Vienna) and 3100 m a.s.l. (BSRN site Sonnblick). The paper outlines the aims and scopes of ARAD, its measurement and calibration standards, methods, strategies and station locations. ARAD network operation uses innovative data processing for quality assurance and quality control, applying manual and automated control algorithms. A combined uncertainty estimate for the broadband shortwave radiation fluxes at all five ARAD stations indicates that accuracies range from 1.5 to 23 %. If a directional response error of the pyranometers and the temperature response of the instruments and the data acquisition system (DAQ) is corrected, this expanded uncertainty reduces to 1.4 to 5.2 %. Thus, for large signals (global: 1000 W m−2, diffuse: 500 W m−2) BSRN target accuracies are met or closely met for 70 % of valid measurements at the ARAD stations after this correction. For small signals (50 W m−2), the targets are not achieved as a result of uncertainties associated with the DAQ or the instrument sensitivities. Additional accuracy gains can be achieved in future by additional measurements and corrections. However, for the measurement of direct solar radiation improved instrument accuracy is needed. ARAD could serve as a powerful example for establishing state-of-the-art radiation monitoring at the national level with a multiple-purpose approach. Instrumentation, guidelines and tools (such as the data quality control) developed within ARAD are best practices which could be adopted in other regions, thus saving high development costs.

scholarly journals Diffuse solar radiation and associated meteorological parameters in India

1996 ◽  
Vol 14 (10) ◽  
pp. 1051-1059 ◽  
Author(s):  
A. B. Bhattacharya ◽  
S. K. Kar ◽  
R. Bhattacharya
Keyword(s):  
Solar Radiation ◽  
Meteorological Parameters ◽  
Global Radiation ◽  
Low Frequency ◽  
Diffuse Radiation ◽  
Global Solar Radiation ◽  
Surface Radiation ◽  
Diffuse Solar Radiation ◽  
Sunshine Hours ◽  
The Tropics

Abstract. Solar diffuse radiation data including global radiation, shortwave and longwave balances, net radiation and sunshine hours have been extensively analyzed to study the variation of diffuse radiation with turbidity and cloud discharges appearing in the form of atmospherics over the tropics. Results of surface radiation measurements at Calcutta, Poona, Delhi and Madras are presented together with some meteorological parameters. The monthly values of diffuse radiation and the monthly ratios of diffuse to global solar radiation have been examined, with a special emphasis in relation to the noise level of atmospherics at Calcutta in the very low frequency band. The results exhibit some definite seasonal changes which appear to be in close agreement with one another.

Improved Accuracy Models For Hourly Diffuse Solar Radiation

2005 ◽  
Vol 128 (1) ◽  
pp. 104-117 ◽  
Author(s):  
T. Muneer ◽  
S. Munawwar
Keyword(s):  
Solar Radiation ◽  
Regression Models ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Evaluation Procedure ◽  
Accuracy Score ◽  
Error Statistics ◽  
Diffuse Solar Radiation ◽  
Energy Applications ◽  
Extensive Evaluation

Solar energy applications require readily available, site-oriented, and long-term solar data. However, the frequent unavailability of diffuse irradiation, in contrast to its need, has led to the evolution of various regression models to predict it from the more commonly available data. Estimating the diffuse component from global radiation is one such technique. The present work focuses on improvement in the accuracy of the models for predicting horizontal diffuse irradiation using hourly solar radiation database from nine sites across the globe. The influence of sunshine fraction, cloud cover, and air mass on estimation of diffuse radiation is investigated. Inclusion of these along with hourly clearness index, leads to the development of a series of models for each site. Estimated values of hourly diffuse radiation are compared with measured values in terms of error statistics and indicators like, R2, mean bias deviation, root mean square deviation, skewness, and kurtosis. A new method called “the accuracy score system” is devised to assess the effect on accuracy with subsequent addition of each parameter and increase in complexity of equation. After an extensive evaluation procedure, extricate but adequate models are recommended as optimum for each of the nine sites. These models were found to be site dependent but the model types were fairly consistent for neighboring stations or locations with similar climates. Also, this study reveals a significant improvement from the conventional k-kt regression models to the presently proposed models.

scholarly journals Modelling the amphibian chytrid fungus spread by connectivity analysis: towards a national monitoring network in Italy

2021 ◽  
Author(s):  
Andrea Costa ◽  
Lorenzo Dondero ◽  
Giorgia Allaria ◽  
Bryan Nelson Morales Sanchez ◽  
Giacomo Rosa ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
National Level ◽  
Monitoring Network ◽  
Electric Circuit ◽  
Population Declines ◽  
Climate Data ◽  
Landscape Permeability ◽  
National Monitoring ◽  
Climatic Scenarios ◽  
Amphibian Chytrid Fungus

AbstractThe emerging amphibian disease, Batrachochytrium dendrobatidis (Bd), is driving population declines worldwide and even species extinctions in Australia, South and Central America. In order to mitigate effects of Bd on amphibian populations, high-exposed areas should be identified at the local scale and effective conservation measures should be planned at the national level. This assessment is actually lacking in the Mediterranean basin, and in particular in Italy, one of the most relevant amphibian diversity hotspots in the entire region. In this study, we reviewed the available information on Bd in Italy, and conducted a 5-year molecular screening on 1274 individual skin swabs belonging to 18 species. Overall, we found presence of Bd in 13 species and in a total of 56 known occurrence locations for peninsular Italy and Sardinia. We used these occurrence locations and climate data to model habitat suitability of Bd for current and future climatic scenarios. We then employed electric circuit theory to model landscape permeability to the diffusion of Bd, using a resistance map. With this procedure, we were able to model, for the first time, the diffusion pathways of Bd at the landscape scale, characterising the main future pathways towards areas with a high probability of Bd occurrence. Thus, we identified six national protected areas that will become pivotal for a nationally-based strategic plan in order to monitor, mitigate and possibly contrast Bd diffusion in Italy.

An Assessment of Observed and Simulated Temperature Variability in Sierra de Guadarrama (Spain)

2021 ◽  
Author(s):  
Cristina Vegas Cañas ◽  
J. Fidel González Rouco ◽  
Jorge Navarro Montesinos ◽  
Elena García Bustamante ◽  
Etor E. Lucio Eceiza ◽  
...  
Keyword(s):  
Western Europe ◽  
Climate Model ◽  
Regional Climate ◽  
Monitoring Network ◽  
Horizontal Resolution ◽  
Temperature Variability ◽  
Added Value ◽  
Seasonal Temperature ◽  
Temperature Trends ◽  
Highly Correlated

<p>This work provides a first assessment of temperature variability from interannual to multidecadal timescales in Sierra de Guadarrama, located in central Spain, from observations and regional climate model (RCM) simulations. Observational data are provided by the Guadarrama Monitoring Network (GuMNet; www.ucm.es/gumnet) at higher altitudes, up to 2225 masl, and by the Spanish Meteorological Agency (AEMet) at lower sites. An experiment at high horizontal resolution of 1 km using the Weather Research and Forecasting (WRF) RCM, feeding from ERA Interim inputs, is used. Through model-data comparison, it is shown that the simulations are annually and seasonally highly representative of the observations, although there is a tendency in the model to underestimate observational temperatures, mostly at high altitudes. Results show that WRF provides an added value in relation to the reanalysis, with improved correlation and error metrics relative to observations.</p><p>The analysis of temperature trends shows a warming in the area during the last 20 years, very significant in autumn. When spanning the analysis to the whole observational period, back to the beginning of the 20th century at some sites, significant annual and seasonal temperature increases of 1℃/decade develop, most of them happening during de 1970s, although not as intense as during the last 20 years.</p><p>The temporal variability of temperature anomalies in the Sierra de Guadarrama is highly correlated with the temperatures in the interior of the Iberian Peninsula. This relationship can be extended broadly over south-western Europe.</p>

scholarly journals Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece

2012 ◽  
Vol 12 (12) ◽  
pp. 33265-33289
Author(s):  
A. V. Lindfors ◽  
N. Kouremeti ◽  
A. Arola ◽  
S. Kazadzis ◽  
A. F. Bais ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Atmospheric Aerosol ◽  
Global Radiation ◽  
Single Scattering ◽  
Surface Radiation ◽  
Surface Solar Radiation ◽  
Long Time ◽  
Source Of Information

Abstract. Pyranometer measurements of the solar surface radiation (SSR) are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD) using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, was developed and tested using recent data from Thessaloniki, Greece. The effective AOD calculated using this method was found to agree well with co-located AERONET measurements, exhibiting a correlation coefficient of 0.9 with 2/3 of the data found within ±20% or ±0.05 of the AERONET AOD. This is similar to the performance of current satellite aerosol methods. Differences in the AOD as compared to AERONET can be explained by variations in the aerosol properties of the atmosphere that are not accounted for in the idealized settings used in the radiative transfer simulations, such as variations in the single scattering albedo and Ångström exponent. Furthermore, the method is sensitive to calibration offsets between the radiative transfer simulations and the pyranometer SSR. The method provides an opportunity of extending our knowledge of the atmospheric aerosol load to locations and times not covered by dedicated aerosol measurements.

scholarly journals Comparison of Pyranometric and Pyrheliometric Methods for the Determination of Sunshine Duration

2007 ◽  
Vol 24 (5) ◽  
pp. 835-846 ◽  
Author(s):  
Yvonne B. L. Hinssen ◽  
Wouter H. Knap
Keyword(s):  
Solar Irradiance ◽  
Extreme Values ◽  
Sunshine Duration ◽  
Global Radiation ◽  
Surface Radiation ◽  
Global Irradiance ◽  
Correlation Algorithm ◽  
Mean Differences ◽  
Radiation Measurements

Abstract Two pyranometric methods for the determination of sunshine duration (SD) from global irradiance measurements are evaluated by means of summated sunshine seconds derived from pyrheliometric measurements in combination with the WMO threshold of 120 W m−2 for the direct solar irradiance. The evaluation is performed using direct and global radiation measurements made at the Cabauw Baseline Surface Radiation Network (BSRN) site in the Netherlands for the period March 2005–February 2006. The “Slob algorithm” uses 10-min mean and extreme values of the measured global irradiance and parameterized estimates of the direct and diffuse irradiance. The “correlation algorithm” directly relates SD to 10-min mean measurements of global irradiance. The cumulative pyrheliometric SD for the mentioned period is 1429 h. Relative to this value, the Slob algorithm and correlation algorithm give −72 h (−5%) and +8 h (+0.6%). On a daily mean basis, the values are −0.22 ± 0.05 h day−1 and 0.03 ± 0.03 h day−1, respectively. By means of tuning the irradiance parameterizations of the Slob algorithm, the yearly cumulative and daily mean differences can be reduced to +7 h (+0.5%) and 0.02 ± 0.04 h day−1, respectively. It is concluded that, by use of either algorithm, it is possible to estimate daily sums of SD from 10-min mean measurements of global irradiance with a typical uncertainty of 0.5–0.7 h day−1. For yearly sums, the uncertainty typically amounts to 0.5%.

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