Evaluation of simulated photolysis rates and their response to solar irradiance variability

Sukhodolov, Timofei; Rozanov, Eugene; Ball, William T.; Bais, A. F.; Tourpali, Kleareti; Шапиро, А. И.; Telford, P.; Smyshlyaev, S. P.; Fomin, B. A.; Sander, R.; Bossay, Sébastien; Bekki, Slimane; Marchand, Marion; Chipperfield, Martyn P.; Dhomse, Sandip; Haigh, Joanna D.; Peter, Thomas; Schmutz, W.

doi:10.1002/2015jd024277

Cited by 48 publications

(60 citation statements)

References 70 publications

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“…Although a temperature signal is found (not shown), it is small, hence reducing the likelihood for the solar-induced temperature feedback to be prominent in our experiments. It is worth noting that the upper stratosphere negative lags in our experiments compare very well with those found in CCM experiments of Sukhodolov et al (2017) (see their Fig. 3) despite the fact that their model (SOCOL) also includes the direct radiative heating effect.…”

Section: Observed and Modeled Ozone Response To The Rotational Cyclesupporting

confidence: 88%

“…In particular, it has been shown recently that the photolysis rates calculated by LMDZ-Reprobus and SOCOL can differ substantially (Sukhodolov et al, 2016). The good correspondence between the two sets of model results may thus be fortuitous.…”

Section: Observed and Modeled Ozone Response To The Rotational Cyclementioning

confidence: 87%

“…The photolysis rates used in Reprobus are pre-calculated offline with the Tropospheric and Ultraviolet Visible (TUV) model (Madronich and Flocke, 1999;Sukhodolov et al, 2016) and then tabulated in a look-up table for 101 altitudes, 7 total ozone columns and 27 solar zenith angles. TUV calculates in spherical geometry the actinic flux, scattering and absorption through the atmosphere by the multi-stream discrete ordinate method of Stamnes et al (1988).…”

Section: The Lmdz-reprobus Modelmentioning

confidence: 99%

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Sensitivity of the tropical stratospheric ozone response to the solar rotational cycle in observations and chemistry–climate model simulations

Thiéblemont¹,

Marchand

Bekki

et al. 2017

Atmos. Chem. Phys.

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Abstract. The tropical stratospheric ozone response to solar UV variations associated with the rotational cycle ( ∼ 27 days) is analyzed using MLS satellite observations and numerical simulations from the LMDz-Reprobus chemistry-climate model. The model is used in two configurations, as a chemistry-transport model (CTM) where dynamics are nudged toward ERA-Interim reanalysis and as a chemistry-climate model (free-running) (CCM). An ensemble of five 17-year simulations (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) is performed with the CCM. All simulations are forced by reconstructed time-varying solar spectral irradiance from the Naval Research Laboratory Solar Spectral Irradiance model. We first examine the ozone response to the solar rotational cycle during two 3-year periods which correspond to the declining phases of solar cycle 22 (October 1991-September 1994 and solar cycle 23 (September 2004-August 2007, when the satellite ozone observations of the two Microwave Limb Sounders (UARS MLS and Aura MLS) are available. In the observations, during the first period, ozone and UV flux are found to be correlated between about 10 and 1 hPa with a maximum of 0.29 at ∼ 5 hPa; the ozone sensitivity (% change in ozone for 1 % change in UV) peaks at ∼ 0.4. Correlation during the second period is weaker and has a peak ozone sensitivity of only 0.2, possibly due to the fact that the solar forcing is weaker during that period. The CTM simulation reproduces most of these observed features, including the differences between the two periods. The CCM ensemble mean results comparatively show much smaller differences between the two periods, suggesting that the amplitude of the rotational ozone signal estimated from MLS observations or the CTM simulation is strongly influenced by other (non-solar) sources of variability, notably dynamics. The analysis of the ensemble of CCM simulations shows that the estimation of the ensemble mean ozone sensitivity does not vary significantly either with the amplitude of the solar rotational fluctuations or with the size of the time window used for the ozone sensitivity retrieval. In contrast, the uncertainty of the ozone sensitivity estimate significantly increases during periods of decreasing amplitude of solar rotational fluctuations (also coinciding with minimum phases of the solar cycle), and for decreasing size of the time window analysis. We found that a minimum of 3-and 10-year time window is needed for the 1σ uncertainty to drop below 50 and 20 %, respectively. These uncertainty sources may explain some of the discrepancies found in previous estimates of the ozone response to the solar rotational cycle.

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Section: Observed and Modeled Ozone Response To The Rotational Cyclesupporting

confidence: 88%

Section: Observed and Modeled Ozone Response To The Rotational Cyclementioning

confidence: 87%

Section: The Lmdz-reprobus Modelmentioning

confidence: 99%

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Sensitivity of the tropical stratospheric ozone response to the solar rotational cycle in observations and chemistry–climate model simulations

Thiéblemont¹,

Marchand

Bekki

et al. 2017

Atmos. Chem. Phys.

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“…We use the units of ozone number density, as opposed to volume mixing ratios, in order to avoid uncertainties associated with the choice of temperature record used for the conversion (see e.g. Maycock et al, 2016;Dhomse et al, 2016).…”

Section: The Observation/reanalysis Datasetsmentioning

confidence: 99%

Simulating the atmospheric response to the 11-year solar cycle forcing with the UM-UKCA model: the role of detection method and natural variability

Bednarz¹,

Maycock²,

Telford³

et al. 2018

Preprint

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The 11-year solar cycle forcing is recognised as a potentially important atmospheric forcing; however, there remain uncertainties in characterising the effects of the solar variability on the atmosphere from observations and models. Here we 15 present the first detailed assessment of the atmospheric response to the 11-year solar cycle in the UM-UKCA chemistryclimate model using an ensemble of integrations over the recent past. Comparison of the model simulations is made with observations and reanalysis. Importantly, in contrast to the majority of previous studies of the solar cycle impacts, we pay particular attention to the role of detection method by comparing the results diagnosed using both a composite and a multiple linear regression method. We show that stratospheric solar responses diagnosed using both techniques largely agree with 20 each other within the associated uncertainties; however, the results show that apparently different signals can be identified by the methods in the troposphere and in the tropical lower stratosphere. Lastly, we focus on the role of internal atmospheric variability on the detection of the 11-year solar responses by comparing the results diagnosed from individual model ensemble members (as opposed to those diagnosed from the full ensemble). We show overall agreement between the ensemble members in the tropical and mid-latitude mid-stratosphere-to-lower-mesosphere, but larger apparent differences at 25 NH high latitudes during the dynamically active season. Our results highlight the need for long data sets for confident detection of solar cycle impacts in the atmosphere, as well as for more research on possible interdependence of the solar cycle forcing with other atmospheric forcings and processes (e.g. QBO, ENSO… etc.).Atmos. Chem. Phys. Discuss., https://doi

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“…This is difficult to quantify absolutely, but we would note that the TOMCAT/SLIMCAT photolysis scheme has performed well in intercomparisons of radiative transfer codes (e.g. SPARC CCMVal, 2010;Sukhodolov et al, 2016). For comparisons using a prescribed ozone profile and solar fluxes, SPARC CCMVal (2010) found excellent agreement between models for the calculation of photolysis rates for N 2 O and CFC-11, which are species with similar photolysis sinks to CCl 4 .…”

Section: Tomcat 3-d Chemical Transport Modelmentioning

confidence: 94%

Model sensitivity studies of the decrease in atmospheric carbon tetrachloride

et al. 2016

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Abstract. Carbon tetrachloride (CCl 4 ) is an ozone-depleting substance, which is controlled by the Montreal Protocol and for which the atmospheric abundance is decreasing. However, the current observed rate of this decrease is known to be slower than expected based on reported CCl 4 emissions and its estimated overall atmospheric lifetime. Here we use a three-dimensional (3-D) chemical transport model to investigate the impact on its predicted decay of uncertainties in the rates at which CCl 4 is removed from the atmosphere by photolysis, by ocean uptake and by degradation in soils. The largest sink is atmospheric photolysis (74 % of total), but a reported 10 % uncertainty in its combined photolysis cross section and quantum yield has only a modest impact on the modelled rate of CCl 4 decay. This is partly due to the limiting effect of the rate of transport of CCl 4 from the main tropospheric reservoir to the stratosphere, where photolytic loss occurs. The model suggests large interannual variability in the magnitude of this stratospheric photolysis sink caused by variations in transport. The impact of uncertainty in the minor soil sink (9 % of total) is also relatively small. In contrast,Published by Copernicus Publications on behalf of the European Geosciences Union. 15742 M. P. Chipperfield et al.: Model sensitivity studies of the decrease in atmospheric carbon tetrachloride the model shows that uncertainty in ocean loss (17 % of total) has the largest impact on modelled CCl 4 decay due to its sizeable contribution to CCl 4 loss and large lifetime uncertainty range (147 to 241 years). With an assumed CCl 4 emission rate of 39 Gg year −1 , the reference simulation with the best estimate of loss processes still underestimates the observed CCl 4 (overestimates the decay) over the past 2 decades but to a smaller extent than previous studies. Changes to the rate of CCl 4 loss processes, in line with known uncertainties, could bring the model into agreement with in situ surface and remote-sensing measurements, as could an increase in emissions to around 47 Gg year −1 . Further progress in constraining the CCl 4 budget is partly limited by systematic biases between observational datasets. For example, surface observations from the National Oceanic and Atmospheric Administration (NOAA) network are larger than from the Advanced Global Atmospheric Gases Experiment (AGAGE) network but have shown a steeper decreasing trend over the past 2 decades. These differences imply a difference in emissions which is significant relative to uncertainties in the magnitudes of the CCl 4 sinks.

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Evaluation of simulated photolysis rates and their response to solar irradiance variability

Cited by 48 publications

References 70 publications

Sensitivity of the tropical stratospheric ozone response to the solar rotational cycle in observations and chemistry–climate model simulations

Sensitivity of the tropical stratospheric ozone response to the solar rotational cycle in observations and chemistry–climate model simulations

Simulating the atmospheric response to the 11-year solar cycle forcing with the UM-UKCA model: the role of detection method and natural variability

Model sensitivity studies of the decrease in atmospheric carbon tetrachloride

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