scholarly journals 1.2 The impact of solar variability on climate

Keyword(s):  
2017 ◽  
Author(s):  
Amanda C. Maycock ◽  
Katja Matthes ◽  
Susann Tegtmeier ◽  
Hauke Schmidt ◽  
Rémi Thiéblemont ◽  
...  

Abstract. The impact of changes in incoming solar irradiance on stratospheric ozone abundances should be included in climate model simulations to fully capture the atmospheric response to solar variability. This study presents the first systematic comparison of the solar-ozone response (SOR) during the 11 year solar cycle amongst different chemistry-climate models (CCMs) and ozone databases specified in climate models that do not include chemistry. We analyse the SOR in eight CCMs from the WCRP/SPARC Chemistry-Climate Model Initiative (CCMI-1) and compare these with three ozone databases: the Bodeker Scientific database, the SPARC/AC&C database for CMIP5, and the SPARC/CCMI database for CMIP6. The results reveal substantial differences in the representation of the SOR between the CMIP5 and CMIP6 ozone databases. The peak amplitude of theSOR in the upper stratosphere (1–5 hPa) decreases from 5 % to 2 % between the CMIP5 and CMIP6 databases. This difference is because the CMIP5 database was constructed from a regression model fit to satellite observations, whereas the CMIP6 database is constructed from CCM simulations, which use a spectral solar irradiance (SSI) dataset with relatively weak UV forcing. The SOR in the CMIP6 ozone database is therefore implicitly more similar to the SOR in the CCMI-1 models than to the CMIP5 ozone database, which shows a greater resemblance in amplitude and structure to the SOR in the Bodeker database. The latitudinal structure of the annual mean SOR in the CMIP6 ozone database and CCMI-1 models is considerably smoother than in the CMIP5 database, which shows strong gradients in the SOR across the midlatitudes owing to the paucity of observations at high latitudes. The SORs in the CMIP6 ozone database and in the CCMI-1 models show a strong seasonal dependence, including large meridional gradients at mid to high latitudes during winter; such seasonal variations in the SOR are not included in the CMIP5 ozone database. Sensitivity experiments with a global atmospheric model without chemistry (ECHAM6.3) are performed to assess the impact of changes in the representation of the SOR and SSI forcing between CMIP5 and CMIP6. The experiments show that the smaller amplitude of the SOR in the CMIP6 ozone database compared to CMIP5 causes a decrease in the modelled tropical stratospheric temperature response over the solar cycle of up to 0.6 K, or around 50 % of the total amplitude. The changes in the SOR explain most of the difference in the amplitude of the tropical stratospheric temperature response in the case with combined changes in SOR and SSI between CMIP5 and CMIP6. The results emphasise the importance of adequately representing the SOR in climate models to capture the impact of solar variability on the atmosphere. Since a number of limitations in the representation of the SOR in the CMIP5 ozone database have been identified, CMIP6 models without chemistry are encouraged to use the CMIP6 ozone database to capture the climate impacts of solar variability.


Author(s):  
Nur Izzati Zolkifr ◽  
Chin Kim Gan ◽  
Meysam Shamsiri

<span>The widespread of Photovoltaic (PV) systems as one of the distributed generation technologies could have profound impact on the distribution networks operation, particularly on network losses and network voltages fluctuations. This is mainly caused by the high PV penetrations coupled with high solar variability in the countries with large cloud cover. Therefore, this paper presents an investigation on the impact of residential grid-connected PV system by utilizing a typical low voltage (LV) network in Malaysia under various solar variability days. In this study, there are three scenarios; where, each scenario were performed with different levels of PV penetration and five different solar variability days. The impacts of PV system allocation in different scenarios and various solar variability days are assessed in term of voltage unbalance and network losses. The results propose that Scenario 1: randomly allocation of PV systems across the LV network has the lowest voltage unbalance and network losses especially during overcast day</span>


2016 ◽  
Author(s):  
A. Maycock ◽  
K. Matthes ◽  
S. Tegtmeier ◽  
R. Thiéblemont ◽  
L. Hood

Abstract. The impact of changes in incoming solar ultraviolet irradiance on stratospheric ozone forms an important part of the climate response to solar variability. To realistically simulate the climate response to solar variability using climate models, a minimum requirement is that they should include a solar cycle ozone component that has a realistic amplitude and structure, and which varies with season. For climate models that do not include interactive ozone chemistry, this component must be derived from observations and/or chemistry–climate model simulations and included in an externally prescribed ozone database that also includes the effects of all major external forcings. Part 1 of this two part study presents the solar-ozone responses in a number of updated satellite datasets for the period 1984–2004, including the Stratospheric Aerosol and Gas Experiment (SAGE) II version 6.2 and version 7.0 data, and the Solar Backscatter Ultraviolet Instrument (SBUV) version 8.0 and version 8.6 data. A number of combined datasets, which have extended SAGE II using more recent satellite measurements, are also analysed for the period 1984–2011. It is shown that SAGE II derived solar-ozone signals are sensitive to the independent temperature measurements used to convert ozone number density to mixing ratio units. A change in these temperature measurements in the recent SAGE II v7.0 data leads to substantial differences in the mixing ratio solar-ozone response compared to the previous v6.2, particularly in the tropical upper stratosphere. We also show that alternate satellite ozone datasets have issues (e.g., sparse spatial and temporal sampling, low vertical resolution, and shortness of measurement record), and that the methods of accounting for instrument offsets and drifts in merged satellite datasets can have a substantial impact on the solar cycle signal in ozone. For example, the magnitude of the solar-ozone response varies by around a factor of two across different versions of the SBUV VN8.6 record, which appears to be due to the methods used to combine the separate SBUV timeseries. These factors make it difficult to extract more than an annual-mean solar-ozone response from the available satellite observations. It is therefore unlikely that satellite ozone measurements alone can be applied to estimate the necessary solar cycle ozone component of the prescribed ozone database for future coupled model intercomparison projects (e.g., CMIP6).


Science ◽  
1996 ◽  
Vol 272 (5264) ◽  
pp. 981-984 ◽  
Author(s):  
J. D. Haigh
Keyword(s):  

2017 ◽  
Vol 13 (9) ◽  
pp. 1199-1212 ◽  
Author(s):  
Mikhaël Schwander ◽  
Marco Rohrer ◽  
Stefan Brönnimann ◽  
Abdul Malik

Abstract. The impact of solar variability on weather and climate in central Europe is still not well understood. In this paper we use a new time series of daily weather types to analyse the influence of the 11-year solar cycle on the tropospheric weather of central Europe. We employ a novel, daily weather type classification over the period 1763–2009 and investigate the occurrence frequency of weather types under low, moderate, and high solar activity level. Results show a tendency towards fewer days with westerly and west-southwesterly flow over central Europe under low solar activity. In parallel, the occurrence of northerly and easterly types increases. For the 1958–2009 period, a more detailed view can be gained from reanalysis data. Mean sea level pressure composites under low solar activity also show a reduced zonal flow, with an increase of the mean blocking frequency between Iceland and Scandinavia. Weather types and reanalysis data show that the 11-year solar cycle influences the late winter atmospheric circulation over central Europe with colder (warmer) conditions under low (high) solar activity.


2017 ◽  
Author(s):  
Mikhaël Schwander ◽  
Marco Rohrer ◽  
Stefan Brönnimann ◽  
Abdul Malik

Abstract. The impact of solar variability on weather and climate in Central Europe is still not well understood. In this paper we use a new time series of daily weather types to analyse the influence of the 11-year solar cycle on the tropospheric weather of Central Europe. We employ a novel, daily weather type classification over the period 1763–2009 and investigate the occurrence frequency of weather types under low, moderate and high solar activity level. Results show a tendency towards fewer days with westerly and west south-westerly flow over Central Europe under low solar activity. In parallel, the occurrence of northerly and easterly types increases. Changes are consistent across different sub-periods. For the 1958–2009 period, a more detailed view can be gained from reanalysis data. Mean sea level pressure composites under low solar activity also show a reduced zonal flow, with an increase of the mean blocking frequency between Iceland and Scandinavia. Weather types and reanalysis data show that the 11-year solar cycle influences the late winter atmospheric circulation over Central Europe with colder (warmer) conditions under low (high) solar activity. Model simulations used for a comparison do not reproduce the imprint of the 11-year solar cycle found in the reanalyses data.


Author(s):  
Manajit Sengupta

Clouds, aerosols, water vapor and other atmospheric constituents influence solar energy reaching the earth’s surface. Each of these atmospheric constituents has it’s own inherent scale of temporal and spatial variability and they in turn influence the variability in the amount of solar radiation reaching the earth’s surface. This combined influence of the atmospheric constituents and their separate variability characteristics makes solar variability modeling a complicated task. Output from photovoltaic (PV) power plants is dependent on the amount of solar energy reaching the surface. Therefore variability in solar radiation results in variability in PV plant output. The issue of variability in PV plant output has become important in the last couple of years as utility scale PV plants go online and increase in size. Understanding variability in PV plant output requires an understanding of (a) the spatial and temporal variability of solar radiation; (b) the influence of this solar variability on PV plant output. The goal of this paper is to understand what temporal and spatial scales of variability in Global Horizontal Radiation (GHI) are important to a PV plants and what measurements are needed to be able to characterize them. As solar radiation measuring instruments are point receivers it is important to understand how those measurements translate to energy received over a larger spatial extent. Also of importance is the temporal nature of variability characterized not at a single point on the ground but over large spatial areas. In this research we use high temporal and spatial resolution measurements from multiple time synchronized solar radiation sensors to create solar radiation fields at various spatial and temporal scales using a wide range of interpolation techniques. These solar fields are then used to create plant power output for various size PV plants. As various interpolation schemes can produce different distributions we investigate the impact of interpolation schemes on GHI and power output distribution. While power output from PV plants is an important quantity the temporal variability of power is a matter of concern to utilities. In this paper we show how PV plant output varies across different time scales.


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