130 research outputs found
kms22134/smalley_dessler_2017: Smalley and Dessler 2017 Code
No full textThis release contains updated code for the following published article.
Smalley, K. M., Dessler, A. E., Bekki, S., Deushi, M., Marchand, M., Morgenstern, O., Plummer, D. A., Shibata, K., Yamashita, Y., and Zeng, G.: Contribution of different processes to changes in tropical lower-stratospheric water vapor in chemistry–climate models, Atmos. Chem. Phys., 17, 8031–8044, https://doi.org/10.5194/acp-17-8031-2017, 2017
Long-term variations and trends in the simulation of the middle atmosphere 1980–2004 by the chemistry-climate model of the Meteorological Research Institute
No full textA middle-atmosphere simulation of the past 25 years (from 1980 to 2004) has
been performed with a chemistry-climate model (CCM) of the Meteorological
Research Institute (MRI) under observed forcings of sea-surface temperature,
greenhouse gases, halogens, volcanic aerosols, and solar irradiance
variations. The dynamics module of MRI-CCM is a spectral global model
truncated triangularly at a maximum wavenumber of 42 with 68 layers
extending from the surface to 0.01 hPa (about 80 km), wherein the vertical
spacing is 500 m from 100 to 10 hPa. The chemistry-transport module treats 51
species with 124 reactions including heterogeneous reactions. Transport of
chemical species is based on a hybrid semi-Lagrangian scheme, which is a
flux form in the vertical direction and an ordinary semi-Lagrangian form in
the horizontal direction. The MRI-CCM used in this study reproduced a
quasi-biennial oscillation (QBO) of about a 20-month period for wind and
ozone in the equatorial stratosphere. Multiple linear regression analysis
with time lags for volcanic aerosols was performed on the zonal-mean
quantities of the simulated result to separate the trend, the QBO, the El
Chichón and Mount Pinatubo, the 11-year solar cycle, and the El
Niño/Southern Oscillation (ENSO) signals. It is found that MRI-CCM can
more or less realistically reproduce observed trends of annual mean
temperature and ozone, and those of total ozone in each month. MRI-CCM also
reproduced the vertical multi-cell structures of tropical temperature,
zonal-wind, and ozone associated with the QBO, and the mid-latitude total
ozone QBO in each winter hemisphere. Solar irradiance variations of the
11-year cycle were found to affect radiation alone (not photodissociation)
because of an error in making the photolysis lookup table. Nevertheless,
though the heights of the maximum temperature (ozone) in the tropics are
much higher (lower) than observations, MRI-CCM could reproduce the second
maxima of temperature and ozone in the lower stratosphere, demonstrating
that the dynamic effect outweighs the photochemical effect there. The ENSO
signals of annual mean temperature, zonal wind, and ozone are generally
reproduced in the troposphere and below the middle stratosphere. The
volcanic signals of temperature increase and ozone decrease are much
overestimated for both El Chichón and Mount Pinatubo
Long-term variations and trends in the simulation of the middle atmosphere 1980–2004 by the chemistry-climate model of the Meteorological Research Institute
No full textAbstract. A middle-atmosphere simulation of the past 25 years (from 1980 to 2004) has been performed with a chemistry-climate model (CCM) of the Meteorological Research Institute (MRI) under observed forcings of sea-surface temperature, greenhouse gases, halogens, volcanic aerosols, and solar irradiance variations. The dynamics module of MRI-CCM is a spectral global model truncated triangularly at a maximum wavenumber of 42 with 68 layers extending from the surface to 0.01 hPa (about 80 km), wherein the vertical spacing is 500 m from 100 to 10 hPa. The chemistry-transport module treats 51 species with 124 reactions including heterogeneous reactions. Transport of chemical species is based on a hybrid semi-Lagrangian scheme, which is a flux form in the vertical direction and an ordinary semi-Lagrangian form in the horizontal direction. The MRI-CCM used in this study reproduced a quasi-biennial oscillation (QBO) of about a 20-month period for wind and ozone in the equatorial stratosphere. Multiple linear regression analysis with time lags for volcanic aerosols was performed on the zonal-mean quantities of the simulated result to separate the trend, the QBO, the El Chichón and Mount Pinatubo, the 11-year solar cycle, and the El Niño/Southern Oscillation (ENSO) signals. It is found that MRI-CCM can more or less realistically reproduce observed trends of annual mean temperature and ozone, and those of total ozone in each month. MRI-CCM also reproduced the vertical multi-cell structures of tropical temperature, zonal-wind, and ozone associated with the QBO, and the mid-latitude total ozone QBO in each winter hemisphere. Solar irradiance variations of the 11-year cycle were found to affect radiation alone (not photodissociation) because of an error in making the photolysis lookup table. Nevertheless, though the heights of the maximum temperature (ozone) in the tropics are much higher (lower) than observations, MRI-CCM could reproduce the second maxima of temperature and ozone in the lower stratosphere, demonstrating that the dynamic effect outweighs the photochemical effect there. The ENSO signals of annual mean temperature, zonal wind, and ozone are generally reproduced in the troposphere and below the middle stratosphere. The volcanic signals of temperature increase and ozone decrease are much overestimated for both El Chichón and Mount Pinatubo.
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Global Surface Ozone Concentration Dataset 1990-2017 Mapped at Fine Resolution through the Bayesian Maximum Entropy Data Fusion of Observations and Model Output
No full textThis global surface ozone concentration dataset corresponds to the data developed in this paper:
DeLang, M. N., J. S. Becker, K.-L. Chang, M. L. Serre, O. R. Cooper, M. G. Schultz, S. Schroder, X. Lu, L. Zhang, M. Deushi, B. Josse, C. A. Keller, J.-F. Lamarque, M. Lin, J. Liu, V. Marecal, S. A. Strode, K. Sudo, S. Tilmes, L. Zhang, S. Cleland, E. Collins, M. Brauer, and J. J. West (2021) Mapping yearly fine resolution global surface ozone through the Bayesian Maximum Entropy data fusion of observations and model output for 1990-2017, Environmental Science & Technology, 55, 4389-4398, doi: 10.1021/acs.est.0c07742.
Ozone concentrations are estimated as described in the paper, with output shown for the Ozone Season Daily Maximum 8-hr metric (OSDMA8) for each year between 1990 and 2017, at 0.1 degree spatial resolution. Ozone is estimated through data fusion of output from several global models, with observations of ozone collected by TOAR. The data fusion involves application of the M3Fusion method to create a multi-model composite of several global models, followed by BME data fusion, as described in the paper.
The *.nc file contains the latitude, longitude, ozone concentration estimate, and estimated variance for each 0.1 x 0.1 degree grid cell.
Please contact Jason West ([email protected]) with questions about the dataset. We'd like to hear from you to know how you're using the data!Please contact Jason West ([email protected]) with questions about the dataset. We would like to hear from you about how you're using the data!
We acknowledge support from the NASA Health and Air Quality Applied Sciences Team (#NNX16AQ30G) and the
National Institute for Occupational Safety and Health (T42-OH008673). M.D. was supported by the Japan Society for the
Promotion of Science (JP20K04070)
Multimodel climate and variability of the stratosphere
No full textThe stratospheric climate and variability from simulations of sixteen chemistry‐climate models is evaluated. On average the polar night jet is well reproduced though its variability is less well reproduced with a large spread between models. Polar temperature biases are less than 5 K except in the Southern Hemisphere (SH) lower stratosphere in spring. The accumulated area of low temperatures responsible for polar stratospheric cloud formation is accurately reproduced for the Antarctic but underestimated for the Arctic. The shape and position of the polar vortex is well simulated, as is the tropical upwelling in the lower stratosphere. There is a wide model spread in the frequency of major sudden stratospheric warnings (SSWs), late biases in the breakup of the SH vortex, and a weak annual cycle in the zonal wind in the tropical upper stratosphere. Quantitatively, “metrics” indicate a wide spread in model performance for most diagnostics with systematic biases in many, and poorer performance in the SH than in the Northern Hemisphere (NH). Correlations were found in the SH between errors in the final warming, polar temperatures, the leading mode of variability, and jet strength, and in the NH between errors in polar temperatures, frequency of major SSWs, and jet strength. Models with a stronger QBO have stronger tropical upwelling and a colder NH vortex. Both the qualitative and quantitative analysis indicate a number of common and long‐standing model problems, particularly related to the simulation of the SH and stratospheric variability
Northern winter stratospheric temperature and ozone responses to ENSO inferred from an ensemble of Chemistry Climate Models
No full textThe connection between the El Ni˜no Southern Oscillation (ENSO) and the Northern polar stratosphere has been established from observations and atmospheric modeling. Here a systematic inter-comparison of the sensitivity of the modeled stratosphere to ENSO in Chemistry Climate Models (CCMs) is reported. This work uses results from a number of the CCMs included in the 2006 ozone assessment. In the lower stratosphere, the mean of all model simulations reports a warming of the polar vortex during strong ENSO events in February–March, consistent with but smaller than the estimate from satellite observations and ERA40 reanalysis. The anomalous warming is associated with an anomalous dynamical increase of column ozone north of 70� N that is accompanied by coherent column ozone decrease in the Tropics, in agreement with that deduced from the NIWA column ozone database, implying an increased residual circulation in the mean of all model simulations during ENSO. The spread in the model responses is partly due to the large internal stratospheric variability and it is shown that it crucially depends on the representation of the tropospheric ENSO teleconnection in the models
Climate and stratospheric ozone during the mid-Holocene and Last Interglacial simulated by MRI-ESM2.0
No full textThe climates of the mid-Holocene (MH) and Last Interglacial (LIG) are characterised by warm periods caused by astronomical forcing and climate feedback. One potential feedback is variation in the stratospheric ozone, the influence of which would extend down to the troposphere, potentially affecting the climate. However, little is known about the role of changes in the stratospheric ozone during past warm interglacial periods. Here, we employ MRI-ESM2.0, an Earth system model with an interactive ozone model, and simulate the climate and atmospheric ozone during the MH and LIG. We show that the vertical and seasonal changes of stratospheric ozone in the LIG exhibited a stronger variation in the stratospheric ozone compared to that in the MH, indicating that both obliquity and precession forcings affect the stratospheric ozone distributions. We further show that ozone feedbacks decrease the surface air temperature by ∼ 0.35 and ∼ 0.25 K in the high-latitude regions of the northern hemisphere in MH and LIG, respectively, while the impact on the zonal mean surface air temperature around Antarctica is small. This is the opposite of the previous finding that implies the importance of ozone in southern hemisphere climates, indicating the need for further assessment of how dynamic ozone variations affect climate and atmospheric structures during past warm interglacial periods using multiple Earth system models.</p
Large Impacts, Past and Future, of Ozone-Depleting Substances on Brewer-Dobson Circulation Trends: A Multimodel Assessment
No full textSubstantial increases in the atmospheric concentration of well‐mixed greenhouse gases (notably CO2), such as those projected to occur by the end of the 21st century under large radiative forcing scenarios, have long been known to cause an acceleration of the Brewer‐Dobson circulation (BDC) in climate models. More recently, however, several single‐model studies have proposed that ozone‐depleting substances might also be important drivers of BDC trends. As these studies were conducted with different forcings over different periods, it is difficult to combine them to obtain a robust quantitative picture of the relative importance of ozone‐depleting substances as drivers of BDC trends. To this end, we here analyze—over identical past and future periods—the output from 20 similarly forced models, gathered from two recent chemistry‐climate modeling intercomparison projects. Our multimodel analysis reveals that ozone‐depleting substances are responsible for more than half of the modeled BDC trends in the two decades 1980–2000. We also find that, as a consequence of the Montreal Protocol, decreasing concentrations of ozone‐depleting substances in coming decades will strongly decelerate the BDC until the year 2080, reducing the age‐of‐air trends by more than half, and will thus substantially mitigate the impact of increasing CO2. As ozone‐depleting substances impact BDC trends, primarily, via the depletion/recovery of stratospheric ozone over the South Pole, they impart seasonal and hemispheric asymmetries to the trends which may offer opportunities for detection in coming decades
Clear sky UV simulations for the 21st century based on ozone and temperature projections from Chemistry-Climate Models
No full textWe have estimated changes in surface solar ultraviolet
(UV) radiation under cloud free conditions in the
21st century based on simulations of 11 coupled Chemistry-
Climate Models (CCMs). The total ozone columns and vertical
profiles of ozone and temperature projected from CCMs
were used as input to a radiative transfer model in order
to calculate the corresponding erythemal irradiance levels.
Time series of monthly erythemal irradiance received at the
surface during local noon are presented for the period 1960
to 2100. Starting from the first decade of the 21st century, the
surface erythemal irradiance decreases globally as a result of
the projected stratospheric ozone recovery at rates that are
larger in the first half of the 21st century and smaller towards
its end. This decreasing tendency varies with latitude, being
more pronounced over areas where stratospheric ozone has been depleted the most after 1980. Between 2000 and
2100 surface erythemal irradiance is projected to decrease
over midlatitudes by 5 to 15%, while at the southern high latitudes
the decrease is twice as much. In this study we have not
included effects from changes in cloudiness, surface reflectivity
and tropospheric aerosol loading, which will likely be
affected in the future due to climate change. Consequently,
over some areas the actual changes in future UV radiation
may be different depending on the evolution of these parameters
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