Simulation of aerosol optical properties over a tropical urban site in India using a global model and its comparison with ground measurements

Abstract. Aerosols have great impacts on atmospheric environment, human health, and earth's climate. Therefore, information on their spatial and temporal distribution is of paramount importance. Despite numerous studies have examined the variation and trends of BC and AOD over India, only very few have focused on their spatial distribution or even correlating the observations with model simulations. In the present study, a three-dimensional aerosol transport-radiation model coupled with a general circulation model. SPRINTARS, simulated atmospheric aerosol distributions including BC and aerosol optical properties, i.e., aerosol optical thickness (AOT), Ångström Exponent (AE), and single scattering albedo (SSA). The simulated results are compared with both BC measurements by aethalometer and aerosol optical properties measured by ground-based skyradiometer and by satellite sensor, MODIS/Terra over Hyderabad, which is a tropical urban area of India, for the year 2008. The simulated AOT and AE in Hyderabad are found to be comparable to ground-based measured ones. The simulated SSA tends to be higher than the ground-based measurements. Both these comparisons of aerosol optical properties between the simulations with different emission inventories and the measurements indicate that, firstly the model uncertainties derived from aerosol emission inventory cannot explain the gaps between the simulations and the measurements and secondly the vertical transport of BC and the treatment of BC-containing particles can be the main issue in the global model to solve the gap.

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A new radiation infrastructure for the Modular Earth Submodel System (MESSy, based on version 2.51)

10.5194/gmd-2015-277 ◽

2016 ◽

Cited By ~ 1

Author(s):

Simone Dietmüller ◽

Patrick Jöckel ◽

Holger Tost ◽

Markus Kunze ◽

Cathrin Gellhorn ◽

...

Keyword(s):

Optical Properties ◽

Atmospheric Chemistry ◽

Radiative Forcing ◽

General Circulation ◽

Circulation Model ◽

Shortwave Radiation ◽

Aerosol Optical Properties ◽

On Line ◽

User Friendly ◽

Radiation Scheme

Abstract. The Modular Earth Submodel System (MESSy) provides an interface to couple submodels to a basemodel via a highly flexible data management facility (Jöckel et al., 2010). In the present paper we present the four new radiation related submodels RAD, AEROPT, CLOUDOPT and ORBIT. The submodel RAD (with shortwave radiation scheme RAD_FUBRAD) simulates the radiative transfer, the submodel AEROPT calculates the aerosol optical properties, the submodel CLOUDOPT calculates the cloud optical properties, and the submodel ORBIT is responsible for Earth orbit calculations. These submodels are coupled via the standard MESSy infrastructure and are largely based on the original radiation scheme of the general circulation model ECHAM5, however, expanded with additional features. These features comprise, among others, user-friendly and flexibly controllable (by namelists) on-line radiative forcing calculations by multiple diagnostic calls of the radiation routines. With this, it is now possible to calculate radiative forcing (instantaneous as well as stratosphere adjusted) of various greenhouse gases simultaneously in only one simulation, as well as the radiative forcing of cloud perturbations. Examples of on-line radiative forcing calculations in the ECHAM/MESSy Atmospheric Chemistry (EMAC) model are presented.

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The direct radiative effect of biomass burning aerosols over southern Africa

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-1999-2005 ◽

2005 ◽

Vol 5 (7) ◽

pp. 1999-2018 ◽

Cited By ~ 50

Author(s):

S. J. Abel ◽

E. J. Highwood ◽

J. M. Haywood ◽

M. A. Stringer

Keyword(s):

Optical Properties ◽

Biomass Burning ◽

Land Surface ◽

General Circulation ◽

Surface Albedo ◽

Circulation Model ◽

Radiative Effect ◽

Aerosol Optical Properties ◽

African Region ◽

Biomass Smoke

Abstract. A multi-column radiative transfer code is used to assess the direct radiative effect of biomass burning aerosols over the southern African region during September. The horizontal distribution of biomass smoke is estimated from two sources; i) General Circulation Model (GCM) simulations combined with measurements from the Aerosol Robotic Network (AERONET) of Sun photometers; ii) data from the Moderate resolution Imaging Spectrometer (MODIS) satellite. Aircraft and satellite measurements are used to constrain the cloud fields, aerosol optical properties, vertical structure, and land surface albedo included in the model. The net regional direct effect of the biomass smoke is -3.1 to -3.6 Wm-2 at the top of atmosphere, and -14.4 to -17.0 Wm-2 at the surface for the MODIS and GCM distributions of aerosol. The direct radiative effect is shown to be highly sensitive to the prescribed vertical profiles and aerosol optical properties. The diurnal cycle of clouds and the spectral dependency of surface albedo are also shown to play an important role.

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The direct radiative effect of biomass burning aerosols over southern Africa

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-1165-2005 ◽

2005 ◽

Vol 5 (2) ◽

pp. 1165-1211 ◽

Cited By ~ 5

Author(s):

S. J. Abel ◽

E. J. Highwood ◽

J. M. Haywood ◽

M. A. Stringer

Keyword(s):

Optical Properties ◽

Biomass Burning ◽

Land Surface ◽

General Circulation ◽

Surface Albedo ◽

Circulation Model ◽

Radiative Effect ◽

Aerosol Optical Properties ◽

African Region ◽

Biomass Smoke

Abstract. A multi-column radiative transfer code is used to assess the direct radiative effect of biomass burning aerosols over the southern African region during September. The horizontal distribution of biomass smoke is estimated from two sources; i) General Circulation Model (GCM) simulations combined with measurements from the Aerosol Robotic Network (AERONET) of Sun photometers; ii) data from the Moderate resolution Imaging Spectrometer (MODIS) satellite. Aircraft and satellite measurements are used to constrain the cloud fields, aerosol optical properties, vertical structure, and land surface albedo included in the model. The net regional direct effect of the biomass smoke is −3.1 to −3.6 Wm-2 at the top of atmosphere, and −14.4 to −17.0 Wm-2 at the surface for the MODIS and GCM distributions of aerosol. The direct radiative effect is shown to be highly sensitive to the prescribed vertical profiles and aerosol optical properties. The diurnal cycle of clouds and the spectral dependency of surface albedo are also shown to play an important role.

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A new radiation infrastructure for the Modular Earth Submodel System (MESSy, based on version 2.51)

Geoscientific Model Development ◽

10.5194/gmd-9-2209-2016 ◽

2016 ◽

Vol 9 (6) ◽

pp. 2209-2222 ◽

Cited By ~ 26

Author(s):

Simone Dietmüller ◽

Patrick Jöckel ◽

Holger Tost ◽

Markus Kunze ◽

Catrin Gellhorn ◽

...

Keyword(s):

Optical Properties ◽

Atmospheric Chemistry ◽

Radiative Forcing ◽

General Circulation ◽

Circulation Model ◽

Shortwave Radiation ◽

Earth Orbit ◽

Aerosol Optical Properties ◽

User Friendly ◽

Radiation Scheme

Abstract. The Modular Earth Submodel System (MESSy) provides an interface to couple submodels to a base model via a highly flexible data management facility (Jöckel et al., 2010). In the present paper we present the four new radiation related submodels RAD, AEROPT, CLOUDOPT, and ORBIT. The submodel RAD (including the shortwave radiation scheme RAD_FUBRAD) simulates the radiative transfer, the submodel AEROPT calculates the aerosol optical properties, the submodel CLOUDOPT calculates the cloud optical properties, and the submodel ORBIT is responsible for Earth orbit calculations. These submodels are coupled via the standard MESSy infrastructure and are largely based on the original radiation scheme of the general circulation model ECHAM5, however, expanded with additional features. These features comprise, among others, user-friendly and flexibly controllable (by namelists) online radiative forcing calculations by multiple diagnostic calls of the radiation routines. With this, it is now possible to calculate radiative forcing (instantaneous as well as stratosphere adjusted) of various greenhouse gases simultaneously in only one simulation, as well as the radiative forcing of cloud perturbations. Examples of online radiative forcing calculations in the ECHAM/MESSy Atmospheric Chemistry (EMAC) model are presented.

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On the response of a three-dimensional general circulation model to imposed changes in the ozone distribution

Journal of Geophysical Research Atmospheres ◽

10.1029/97jd00529 ◽

1997 ◽

Vol 102 (D11) ◽

pp. 13051-13077 ◽

Cited By ~ 21

Author(s):

B. Christiansen ◽

A. Guldberg ◽

A. W. Hansen ◽

L. P. Riishøjgaard

Keyword(s):

General Circulation Model ◽

General Circulation ◽

Three Dimensional ◽

Circulation Model ◽

Ozone Distribution

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Organization of Numerical Experiments with an Atmospheric General Circulation Model and an Ocean Global Model

Computational Mathematics and Mathematical Physics ◽

10.1134/s0965542521100110 ◽

2021 ◽

Vol 61 (10) ◽

pp. 1661-1671

Author(s):

V. P. Parkhomenko

Keyword(s):

General Circulation Model ◽

Numerical Experiments ◽

General Circulation ◽

Atmospheric General Circulation Model ◽

Circulation Model ◽

Global Model ◽

Atmospheric General Circulation

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Operational ocean models in the Adriatic Sea: a skill assessment

Ocean Science ◽

10.5194/os-4-61-2008 ◽

2008 ◽

Vol 4 (1) ◽

pp. 61-71 ◽

Cited By ~ 25

Author(s):

J. Chiggiato ◽

P. Oddo

Keyword(s):

General Circulation ◽

Mean Squared Error ◽

Three Dimensional ◽

Circulation Model ◽

Remote Sensing Data ◽

Skill Assessment ◽

Regional Models ◽

Operational Systems ◽

Forecasting System ◽

The Mediterranean

Abstract. In the framework of the Mediterranean Forecasting System (MFS) project, the performance of regional numerical ocean forecasting systems is assessed by means of model-model and model-data comparison. Three different operational systems considered in this study are: the Adriatic REGional Model (AREG); the Adriatic Regional Ocean Modelling System (AdriaROMS) and the Mediterranean Forecasting System General Circulation Model (MFS-GCM). AREG and AdriaROMS are regional implementations (with some dedicated variations) of POM and ROMS, respectively, while MFS-GCM is an OPA based system. The assessment is done through standard scores. In situ and remote sensing data are used to evaluate the system performance. In particular, a set of CTD measurements collected in the whole western Adriatic during January 2006 and one year of satellite derived sea surface temperature measurements (SST) allow to asses a full three-dimensional picture of the operational forecasting systems quality during January 2006 and to draw some preliminary considerations on the temporal fluctuation of scores estimated on surface quantities between summer 2005 and summer 2006. The regional systems share a negative bias in simulated temperature and salinity. Nonetheless, they outperform the MFS-GCM in the shallowest locations. Results on amplitude and phase errors are improved in areas shallower than 50 m, while degraded in deeper locations, where major models deficiencies are related to vertical mixing overestimation. In a basin-wide overview, the two regional models show differences in the local displacement of errors. In addition, in locations where the regional models are mutually correlated, the aggregated mean squared error was found to be smaller, that is a useful outcome of having several operational systems in the same region.

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Can we determine what controls the spatio-temporal distribution of d-excess and <sup>17</sup>O-excess in precipitation using the LMDZ general circulation model?

Climate of the Past ◽

10.5194/cp-9-2173-2013 ◽

2013 ◽

Vol 9 (5) ◽

pp. 2173-2193 ◽

Cited By ~ 41

Author(s):

C. Risi ◽

A. Landais ◽

R. Winkler ◽

F. Vimeux

Keyword(s):

General Circulation Model ◽

Order Parameter ◽

General Circulation ◽

Temporal Distribution ◽

Circulation Model ◽

Second Order ◽

Polar Ice ◽

Spatio Temporal ◽

Different Origins ◽

Second Order Parameter

Abstract. Combined measurements of the H218O and HDO isotopic ratios in precipitation, leading to second-order parameter D-excess, have provided additional constraints on past climates compared to the H218O isotopic ratio alone. More recently, measurements of H217O have led to another second-order parameter: 17O-excess. Recent studies suggest that 17O-excess in polar ice may provide information on evaporative conditions at the moisture source. However, the processes controlling the spatio-temporal distribution of 17O-excess are still far from being fully understood. We use the isotopic general circulation model (GCM) LMDZ to better understand what controls d-excess and 17O-excess in precipitation at present-day (PD) and during the last glacial maximum (LGM). The simulation of D-excess and 17O-excess is evaluated against measurements in meteoric water, water vapor and polar ice cores. A set of sensitivity tests and diagnostics are used to quantify the relative effects of evaporative conditions (sea surface temperature and relative humidity), Rayleigh distillation, mixing between vapors from different origins, precipitation re-evaporation and supersaturation during condensation at low temperature. In LMDZ, simulations suggest that in the tropics convective processes and rain re-evaporation are important controls on precipitation D-excess and 17O-excess. In higher latitudes, the effect of distillation, mixing between vapors from different origins and supersaturation are the most important controls. For example, the lower d-excess and 17O-excess at LGM simulated at LGM are mainly due to the supersaturation effect. The effect of supersaturation is however very sensitive to a parameter whose tuning would require more measurements and laboratory experiments. Evaporative conditions had previously been suggested to be key controlling factors of d-excess and 17O-excess, but LMDZ underestimates their role. More generally, some shortcomings in the simulation of 17O-excess by LMDZ suggest that general circulation models are not yet the perfect tool to quantify with confidence all processes controlling 17O-excess.

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Interannual Variations of Summer Monsoons: Sensitivity to Cloud Radiative Forcing

Journal of Climate ◽

10.1175/1520-0442-11.8.1883 ◽

1998 ◽

Vol 11 (8) ◽

pp. 1883-1905 ◽

Cited By ~ 8

Author(s):

O. P. Sharma ◽

H. Le Treut ◽

G. Sèze ◽

L. Fairhead ◽

R. Sadourny

Keyword(s):

Optical Properties ◽

Radiative Forcing ◽

General Circulation ◽

Initial Conditions ◽

Model Simulation ◽

Circulation Model ◽

Interannual Variations ◽

Radiative Effects ◽

High Concentration ◽

Sea Temperature

Abstract The sensitivity of the interannual variations of the summer monsoons to imposed cloudiness has been studied with a general circulation model using the initial conditions prepared from the European Centre for Medium-Range Forecasts analyses of 1 May 1987 and 1988. The cloud optical properties in this global model are calculated from prognostically computed cloud liquid water. The model successfully simulates the contrasting behavior of these two successive monsoons. However, when the optical properties of the observed clouds are specified in the model runs, the simulations show some degradation over India and its vicinity. The main cause of this degradation is the reduced land–sea temperature contrast resulting from the radiative effects of the observed clouds imposed in such simulations. It is argued that the high concentration of condensed water content of clouds over the Indian land areas will serve to limit heating of the land, thereby reducing the thermal contrast that gives rise to a weak Somali jet. A countermonsoon circulation is, therefore, simulated in the vector difference field of 850-hPa winds from the model runs with externally specified clouds. This countermonsoon circulation is associated with an equatorial heat source that is the response of the model to the radiative effects of the imposed clouds. Indeed, there are at least two clear points that can be made: 1) the cloud–SST patterns, together, affect the interannual variability; and 2) with both clouds and SST imposed, the model simulation is less sensitive to initial conditions. Additionally, the study emphasizes the importance of dynamically consistent clouds developing in response to the dynamical, thermal, and moist state of the atmosphere during model integrations.

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