Dust Radiative Forcing Research Articles

A GCM study of the response of the atmospheric water cycle of West Africa and the Atlantic to Saharan dust radiative forcing

Abstract. The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerly flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer over the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0.95 or higher.

Impact of sea-surface dust radiative forcing on the oceanic primary production: A 1D modeling approach applied to the West African coastal waters

[1] The impact of the dust sea-surface forcing (DSSF) on the oceanic Primary Production (PP) is investigated here by using 1D modelling approach coupling an atmospheric radiative transfer model and a simple PP model. Simulations reveal that dust are able to induce a significant decrease of PP due to the attenuation of light by about 15–25% for dust optical depth (DOD) larger than 0.6–0.7 (at 550 nm). For DOD lower than ∼0.2–0.3, the influence of dust on PP is weak (∼5%). In addition to DOD, the important role played by dust single scattering albedo (DSSA) is also shown. Realistic applications over the Senegal coast are studied using SeaWiFS and AERONET observations. The analysis showed that PP could be reduced by about 15–20% during the spring period. This study highlights that dust/light interactions need to be parameterized in coupled ocean-atmosphere models used to estimate PP at regional scales.

Comment on "Aerosol radiative forcing and climate sensitivity deduced from the Last Glacial Maximum to Holocene transition", by P. Chylek and U. Lohmann, Geophys. Res. Lett., 2008

Abstract. In a recent paper, Chylek and Lohmann (2008) used data from the Vostok ice core together with simple energy balance arguments to simultaneously estimate both the dust radiative forcing effect and the climate sensitivity, generating surprisingly high and low values for these respective parameters. However, their results depend critically on their selection of single unrepresentative data points from time series which exhibit a large amount of short-term variability, and are highly unstable with respect to other arbitrarily selected data points. When temporal averages are used in accordance with accepted norms within the paleoclimate community, the results obtained are entirely unremarkable and in line with previous analyses.

Simulation of dust aerosol and its regional feedbacks over East Asia using a regional climate model

Abstract. The ICTP regional climate model (RegCM3) coupled with a desert dust aerosol model is used to simulate the net radiative forcing (short-wave and long-wave) and related climate effects of dust aerosols over East Asia. Two sets of experiments are completed and intercompared, one without (Exp. 1) and one with (Exp. 2) the radiative effects of dust aerosols. The experiments encompass the main dust producing months, February through May, for 10 years (1997–2006), and the simulation results are evaluated against ground station and satellite data. The model captures the basic observed climatology over the area of interest. The spatial and temporal variations of near surface concentration, mass load, optical depth and emission of dust aerosols from the main source regions are reproduced by model. The main model deficiency is an overestimate of dust amounts over the source regions and an underestimate downwind of these source areas, which indicates an underestimate of dust dispersal. Over the desert source regions, the net TOA radiative forcing is positive, while it is small over the other regions as a result of high surface albedo values which reduce the short-wave radiative forcing. The net surface radiative fluxes are decreased by dust and this causes a surface cooling locally up to −1°C. The inclusion of net (short-wave and long-wave) dust radiative forcing leads to a reduction of dust emission in the East Asia source regions, which is mainly caused by an increase in local stability and a corresponding decrease in dust lifting. Our results indicate that dust effects should be included in the assessment of climate change over East Asia.

A regional climate modeling study of the effect of desert dust on the West African monsoon

We investigate the effect of the shortwave radiative forcing of Saharan dust on the West African monsoon with a regional climate model interactively coupled to a dust model. Toward this purpose we intercompare sets of 38 summer monsoon season simulations (1969–2006) with and without dust effects over a domain encompassing most of the African continent and adjacent regions. We find that the main effect of the dust radiative shortwave forcing is to reduce precipitation over the Sahel region. This is in response to cooling over the Sahara, which decreases the meridional gradient of moist static energy and results in a weakening of the monsoon energy pump. The dust effects also cause a strengthening of the southern branch of the African Easterly Jet and a weakening of Tropical Easterly Jet. Over the Sahel the dust forcing causes climate response patterns that are similar to those found during dry years over the Sahel, which suggests that Saharan dust feedbacks might have a role in maintaining drought events over the region. Overall, the inclusion of dust also tends to improve the model simulation of the West African monsoon, as well as African and Tropical Easterly jets. This work focuses on climatic feedback associated to shortwave radiation forcing and should be further completed by the study of dust effect on long‐wave radiation.

Dust and sea surface temperature forcing of the 1930s “Dust Bowl” drought

Droughts over the central United States (US) are modulated by sea surface temperature (SST) variations in the eastern tropical Pacific. Many models, however, are unable to reproduce the severity and spatial pattern of the “Dust Bowl” drought of the 1930s with SST forcing alone. We force an atmosphere general circulation model with 1930s SSTs and model‐generated dust emission from the Great Plains region. The SSTs alone force a drought over the US similar to observations, but with a weaker precipitation anomaly that is centered too far south. Inclusion of dust radiative forcing, centered over the area of observed wind erosion, increases the intensity of the drought and shifts its center northward. While our conclusions are tempered by limited quantitative observations of the dust aerosol load and soil erosion during this period, our study suggests that unprecedented atmospheric dust loading over the continental US exacerbated the “Dust Bowl” drought.

The role of dust in glacial–interglacial cycles

In this work, the possible climate effects of variations in dust flux during the last six glacial cycles (575–0 ka before present (BP)) are investigated. While most past studies investigated the role of dust in equilibrium or in relatively short transient experiments, in the present study, we conduct million-year simulations using a two-dimensional model. Our results show that accounting for increases in atmospheric dust strongly affects the mean annual surface temperature, and more importantly affects the evolution of the ice sheets. We found a similar cooling trend as previous studies due to the direct radiative forcing by dust. We also found that the effect of dust on snow albedo has a significant impact on the speed of ice-sheet retreat. Furthermore, we found that dust radiative forcing emphasizes the asymmetry of the glacial cycles, especially in the cycles that were symmetric in the reference simulation, a finding that could only be observed with multi-glacial cycle simulations.

Effect of Direct Radiative Forcing of Asian Dust on the Meteorological Fields in East Asia during an Asian Dust Event Period

Abstract Coupled and noncoupled models in a grid of 60 × 60 km2 in the eastern Asian domain have been employed to examine the effect of the direct radiative forcing of the Asian dust aerosol on meteorological fields for an intense Asian dust event observed in eastern Asia on 18–23 March 2002. The coupled model consists of the modified fifth-generation Pennsylvania State University–National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) with direct radiative forcing of the Asian dust aerosol through the NCAR Column Radiation Model and the Asian Dust Aerosol Model. The noncoupled model is MM5 without the direct radiative forcing of the Asian dust aerosol. The results indicate that the radiative cooling of the dust aerosol over the high-dust-concentration (HDC) region induces sinking motion and positive pressure perturbation near the surface, whereas the radiative warming of the aerosol near the top of the HDC layer induces rising motion and negative pressure perturbation, thereby enhancing the stable stratification in the dust layer. The induced positive pressure perturbation near the surface causes a dipole shape of the pressure perturbation field by forming a negative pressure perturbation toward the low pressure center downstream near the surface. This negative pressure perturbation is so deep and wide that the perturbation of the meteorological fields extends in the wide and deep regions away from the HDC region. The associated secondary circulation of this pressure perturbation reduces the low-level wind speed in the upstream HDC region but strengthens the downstream wind speed, resulting in reduction of dust emission in the upstream source region and downstream enhancement. Some of the dust aerosols lifted to the higher level by the synoptic rising motion are transported to the downstream direction more quickly with the upper-level strong wind, resulting in a bent-over shape of dust cloud in the downstream region with a maximum concentration near the surface and a secondary maximum in the upper level. The radiative flux convergence between these maximum dust layers produces a warm layer, thereby further enhancing the stable stratification.

Reply to Comment on “How nature foiled the 2006 hurricane forecasts”

The two main objections of Evan [this issue] to our paper are that (1) the 2006 sea surface temperature (SST) in the Atlantic Ocean was actually above normal compared with the long‐term climatology, and (2) the dust radiative forcing in 2006 was not substantially greater than in 2005 and could not have caused the large change in SST.First, we recognize that 2006 was a climatologically warm year. However, the main focus of our study was on the abrupt cooling of the Atlantic SST from 2005 to 2006, not on the long‐term variation. Hence this point is not germane to our study Second, we suggested that Saharan dust may have been important in triggering a series of rapid feedback processes in the ocean‐atmosphere system in the Atlantic in 2006 resulting in conditions that are unfavorable for hurricane formation.Therefore, the real question is, how much initial dust radiative forcing is sufficient to trigger the feedback processes? This is not a simple question to answer, because it depends on the timing of the aerosol forcing and the preexisting state of the large‐scale coupled atmosphere‐landocean system.

Impact of Desert Dust Radiative Forcing on Sahel Precipitation: Relative Importance of Dust Compared to Sea Surface Temperature Variations, Vegetation Changes, and Greenhouse Gas Warming

Abstract The role of direct radiative forcing of desert dust aerosol in the change from wet to dry climate observed in the African Sahel region in the last half of the twentieth century is investigated using simulations with an atmospheric general circulation model. The model simulations are conducted either forced by the observed sea surface temperature (SST) or coupled with the interactive SST using the Slab Ocean Model (SOM). The simulation model uses dust that is less absorbing in the solar wavelengths and has larger particle sizes than other simulation studies. As a result, simulations show less shortwave absorption within the atmosphere and larger longwave radiative forcing by dust. Simulations using SOM show reduced precipitation over the intertropical convergence zone (ITCZ) including the Sahel region and increased precipitation south of the ITCZ when dust radiative forcing is included. In SST-forced simulations, on the other hand, significant precipitation changes are restricted to over North Africa. These changes are considered to be due to the cooling of global tropical oceans as well as the cooling of the troposphere over North Africa in response to dust radiative forcing. The model simulation of dust cannot capture the magnitude of the observed increase of desert dust when allowing dust to respond to changes in simulated climate, even including changes in vegetation, similar to previous studies. If the model is forced to capture observed changes in desert dust, the direct radiative forcing by the increase of North African dust can explain up to 30% of the observed precipitation reduction in the Sahel between wet and dry periods. A large part of this effect comes through atmospheric forcing of dust, and dust forcing on the Atlantic Ocean SST appears to have a smaller impact. The changes in the North and South Atlantic SSTs may account for up to 50% of the Sahel precipitation reduction. Vegetation loss in the Sahel region may explain about 10% of the observed drying, but this effect is statistically insignificant because of the small number of years in the simulation. Greenhouse gas warming seems to have an impact to increase Sahel precipitation that is opposite to the observed change. Although the estimated values of impacts are likely to be model dependent, analyses suggest the importance of direct radiative forcing of dust and feedbacks in modulating Sahel precipitation.

Climate response and radiative forcing from mineral aerosols during the last glacial maximum, pre‐industrial, current and doubled‐carbon dioxide climates

Mineral aerosol impacts on climate through radiative forcing by natural dust sources are examined in the current, last glacial maximum, pre‐industrial and doubled‐carbon dioxide climate. Modeled globally averaged dust loadings change by +88%, +31% and −60% in the last glacial maximum, pre‐industrial and future climates, respectively, relative to the current climate. Model results show globally averaged dust radiative forcing at the top of atmosphere is −1.0, −0.4 and +0.14 W/m2 for the last glacial maximum, pre‐industrial and doubled‐carbon dioxide climates, respectively, relative to the current climate. Globally averaged surface temperature changed by −0.85, −0.22, and +0.06 °C relative to the current climate in the last glacial maximum, pre‐industrial and doubled carbon dioxide climates, respectively, due solely to the dust radiative forcing changes simulated here. These simulations only include natural dust source response to climate change, and neglect possible impacts by human land and water use.

Large Dust Absorption of Infrared Radiation Over Afro-Asian Regions: Evidence for Anthropogenic Impact

There is a large uncertainty in the estimation of dust radiative forcing due to the lack of adequate data about complex spatial and temporal pattern of the radiative properties of dust. Here, we examine the temporal and spatial variability of dust absorption in the thermal infrared over the Afro-Asian regions using satellite data. Large dust absorption (nearly double compared to that of pure dust) was observed in regions with large anthropogenic influence, possibly due to deposition of black carbon on dust particles. While most of the recent estimates of global mean dust radiative forcing predicted net cooling, our studies indicate that there could be large heating due to dust over vast Afro-Asian regions. It appears that large dust heating is due to its interaction with anthropogenic black carbon

Dust aerosols over India and adjacent continents retrieved using METEOSAT infrared radiance Part II: quantification of wind dependence and estimation of radiative forcing

Abstract. Long-range transport of continental dust makes these particles a significant constituent even at locations far from their sources. It is important to study the temporal variations in dust loading over desert regions and the role of meteorology, in order to assess its radiative impact. In this paper, infrared radiance (10.5-12.5 µm), acquired by the METEOSAT-5 satellite (~5-km resolution) during 1999 and 2003 was used to quantify wind dependence of dust aerosols and to estimate the radiative forcing. Our analysis shows that the frequency of occurrence of dust events was higher during 2003 compared to 1999. Since the dust production function depends mainly on the surface wind speed over regions which are dry and without vegetation, the role of surface wind on IDDI was examined in detail. It was found that an increase of IDDI with wind speed was nearly linear and the rate of increase in IDDI with surface wind was higher during 2003 compared to 1999. It was also observed that over the Indian desert, when wind speed was the highest during monsoon months (June to August), the dust production rate was lower because of higher soil moisture (due to monsoon rainfall). Over the Arabian deserts, when the wind speed is the highest during June to August, the dust production rate is also highest, as soil moisture is lowest during this season. Even though nothing can be said precisely on the reason why 2003 had a greater number of dust events, examination of monthly mean soil moisture at source regions indicates that the occurrence of high winds simultaneous with high soil moisture could be the reason for the decreased dust production efficiency in 1999. It appears that the deserts of Northwest India are more efficient dust sources compared to the deserts of Saudi Arabia and Northeast Africa (excluding Sahara). The radiative impact of dust over various source regions is estimated, and the regionally and annually averaged top of the atmosphere dust radiative forcing (short wave, clear-sky and over land) over the entire study region (0-35° N; 30°-100° E) was in the range of -0.9 to +4.5 Wm-2. The corresponding values at the surface were in the range of -10 to -25 Wm-2. Our studies demonstrate that neglecting the diurnal variation of dust can cause errors in the estimation of long wave dust forcing by as much as 50 to 100%, and nighttime retrieval of dust can significantly reduce the uncertainties. A method to retrieve dust aerosols during nighttime is proposed. The regionally and annually averaged long wave dust radiative forcing was +3.4±1.6 Wm-2.

Dust aerosols over India and adjacent continents retrieved using METEOSAT infrared radiance Part I: sources and regional distribution

Abstract. Mineral dust constitutes the single largest contributor to continental aerosols. To accurately assess the impact of dust aerosols on climate, the spatial and temporal distribution of dust radiative properties is essential. Regional characteristics of dust radiative properties, however, are poorly understood. The magnitude and even sign of dust radiative forcing is uncertain, as it depends on a number of parameters, such as vertical distribution of dust, cloud cover and albedo of the underlying surface. In this paper, infrared radiance (10.5-12.5 µm), acquired from the METEOSAT-5 satellite ( resolution), was used to retrieve regional characteristics of dust aerosols for all of 1999. The infrared radiance depression, due to the presence of dust in the atmosphere, has been used as an index of dust load, known as the Infrared Difference Dust Index (IDDI). There have been several studies in the past carried out over the Sahara using IDDI as a measure of dust load. Over the Indian region, however, studies on dust aerosols are sparse. Spatial and temporal variability in dust loading and its regional distribution over various arid and semiarid regions of India and adjacent continents (0-35° N; 30° E-100° E) (excluding Sahara) have been studied and the results are examined along with surface soil conditions (such as vegetation cover and soil moisture). The advantage of the IDDI method is that information on aerosol properties, such as chemical composition or microphysical properties, is not needed. A large day-to-day variation in IDDI was observed over the entire study region, with values ranging from 4 to 22 K. It was observed that dust activity starts by March over the Indian deserts, as well as over deserts of the Africa and Arabian regions. The IDDI reaches maximum during the period of May to August. Regional maps of IDDI, in conjunction with biomass burning episodes (using TERRA satellite fire pixel counts), suggest that large IDDI values observed during the winter months over Northern India could be due to a possible deposition of black carbon on larger dust aerosols. The IDDI values have been compared with another year (i.e. 2003), with a large number of dust storms reported by meteorological departments based on visibility data. During the dry season, the magnitude of the monthly average IDDI during 2003 was slightly higher than that of 1999. The monthly mean IDDI was in the range from 4 to 9 K over the Indian deserts, as well as over the deserts of Africa and Arabia. The maximum IDDI during a month was in the range from 6 to 18 K. Large IDDI values were observed even over vegetated regions (such as the vegetated part of Africa and central India), attributed to the presence of transported dust from nearby deserts.

Aerosol properties and radiative forcing in Hunshan Dake desert, northern China

Aerosol optical and radiative properties of Hunshan Dake (HD) desert were obtained from the ground-based sun/sky radiometer measurements at Sanggen Dalai, China, in the spring of 2001. The impacts of dust on the surface radiative balance were also examined by using the measurements of solar and infrared radiation. High aerosol optical thickness (AOT) mostly corresponded to the occurrence of dust events. The Angström exponent decreased with increasing AOT, and decreased to zero or negative when heavy dust events appeared in the HD desert. The size distributions of aerosols showed a tri-modal structure, one accumulation mode with radius near 0.1 μm and two modes of larger particles with radii 1.3–1.7 μm and 4.5–5.0 μm. For the total and coarse (r>0.6 μm) particles, the effective radius and volume radius increased with the aerosol content when the AOT was less than 0.6, but decreased with the aerosol content when the AOT was higher than 0.6. The real parts showed a behavior of low sensitivity to wavelength, 1.41–1.58 at 440, 670, 870 and 1020 nm. The imaginary parts also showed lower sensitivity to wavelength with a value of about 0.0007–0.0033 at the same four wavelengths. The absorption became a relative important component in extinction because of the effects of dust particles. The single scattering albedo performed little variation at four wavelengths, 0.97–0.99 for the fine (r<0.6 μm) particles and 0.90–0.98 for the coarse (r>0.6 μm) particles. The asymmetry factors also showed little variation with the increasing AOT, 0.61–0.72 at four wavelengths. In comparison with the clear days, the solar downward radiation decreased by about 51–69% and the infrared downward radiation increased by about 16–36% on dusty days on the surface. The dust of HD desert could lead to a temperature reduction on the surface depending on the offsetting combination of positive solar balance and negative infrared balance during daytime. The dust radiative forcing played an important role in the development of the dust event.

Regional distribution of absorbing efficiency of dust aerosols over India and adjacent continents inferred using satellite remote sensing

The investigations as part of ACE‐Asia have demonstrated that dust we observe may not be just dust, but it may be dust mixed with other aerosols. Consequently dust radiative forcing (even its sign) has a large uncertainty due to the lack of database on complex spatial and temporal pattern of dust radiative properties. To accurately predict the impact of dust aerosols on climate the spatial and temporal distribution of dust radiative properties is essential. Here, we propose a method to infer regional distribution of dust radiative properties using satellite remote sensing (infrared and visible/UV channels) and demonstrate its application. Our studies show that dust in desert areas is low absorbing type while those transported to other locations having anthropogenic activities are significantly more absorbing than pure dust aerosols. This provides a strong evidence for the possible mixing of dust aerosols with other aerosols such as black carbon.

Feedback upon dust emission by dust radiative forcing through the planetary boundary layer

Large changes to the amount of airborne soil particles (or “mineral dust” aerosol) inferred from the climate record raise the question of whether radiative forcing by dust particles amplifies or else diminishes these changes. A previous study with an atmospheric general circulation model (AGCM) indicates that dust radiative forcing in the present‐day climate reduces emission of dust into the atmosphere. Here, we interpret this reduction as an interaction between dust radiative forcing and the planetary boundary layer (PBL). By reducing sunlight incident upon the surface, dust decreases the turbulent flux of sensible heat into the atmosphere. This reduces turbulent mixing within the PBL, along with the downward transport of momentum to the surface, resulting in a decrease of surface wind speed and dust emission. We illustrate this mechanism by comparing the diurnal cycle of emission simulated by two versions of an AGCM, one containing dust radiative forcing, and the other with this forcing set to zero. At some of the most productive source regions, morning emission is reduced in proportion to the surface radiative forcing. We suggest that this negative feedback is underestimated by the AGCM.

Modeling Arabian dust mobilization during the Asian summer monsoon: The effect of prescribed versus calculated SST

Emission of soil (or ‘mineral’) dust aerosol over the Arabian Peninsula during the Northern Hemisphere (NH) summer monsoon increases in response to dust radiative forcing in an atmospheric general circulation model (AGCM) with prescribed sea surface temperature (SST). Radiative heating within the dust layer reinforces the monsoon circulation, which is further strengthened by column latent heating through a wind‐evaporative feedback. The strengthened circulation raises additional dust into the atmosphere over Arabia. In contrast, this positive feedback is absent when SST is calculated by the AGCM using a mixed‐layer ocean. This discrepancy results from the surface energy constraint in the mixed‐layer experiment, where surface evaporation is decreased by the reduction of sunlight beneath the dust layer. In contrast, evaporation and column latent heating increase in the prescribed SST experiment, where the surface energy constraint is absent. Realization of the positive feedback exhibited by the prescribed SST experiment requires that anomalous ocean heat transport (which is not included here) balance the surface radiative forcing by dust.

Surface radiative forcing by soil dust aerosols and the hydrologic cycle

For absorbing aerosols like soil (or “mineral”) dust, radiative forcing at the surface differs substantially from the value at the top of the atmosphere (TOA). The climate response depends not only upon the TOA forcing, but its difference with respect to the surface value, which represents radiative heating within the atmosphere. Surface forcing alters evaporation and the hydrologic cycle, which feeds back upon the aerosol burden through the efficiency of wet deposition. We calculate the surface forcing by soil dust aerosols and its global sensitivity by varying aspects of the dust distribution that are poorly constrained by observations. Ignorance of the global dust burden corresponds to a forcing uncertainty of over a factor of two, with smaller uncertainties due to imprecise knowledge of particle optical properties and the particle size distribution. While global evaporation and precipitation are reduced in response to surface radiative forcing by dust, precipitation increases locally over desert regions, so that dust emission can act as a negative feedback to desertification. The effect of the global reduction in precipitation is to lengthen the particle lifetime by reducing the efficiency of wet deposition, representing a positive feedback upon the global dust burden. For the current climate, we calculate the reduction in wet deposition by dust radiative forcing and find that the aerosol burden is increased only modestly. However, the global dust burden and associated radiative forcing are substantially higher during glacial climates, so that the amplification of the dust load by this feedback is larger. By extrapolating from its radiative forcing in the current climate, we estimate that dust reduces precipitation during glacial times by as much as half the reduction due to the colder climate alone.

Interactive soil dust aerosol model in the GISS GCM: 1. Sensitivity of the soil dust cycle to radiative properties of soil dust aerosols

The sensitivity of the soil dust aerosol cycle to radiative forcing by the soil dust aerosol particles themselves is studied. Four experiments with the NASA GISS atmospheric general circulation model, which includes a soil dust aerosol model, are compared, all using a prescribed climatological sea surface temperature as a lower boundary condition. In one experiment, dust is included as a dynamic tracer with no radiative effect, whereas dust interacts with radiation in the other simulations. The single‐scattering albedo of dust particles is prescribed to be globally uniform in the experiments with radiatively active dust, although this albedo is varied from experiment to experiment. On a global scale the radiative forcing by dust generally causes a reduction in the atmospheric dust load, corresponding to a decreased dust source flux. The dust source flux and its changes are analyzed in more detail for the main source regions. This analysis shows that the reduction varies both with the season and with the single‐scattering albedo of the dust particles. The experiments show that dust radiative forcing can lead to significant changes both in the soil dust cycle and in the climate state. To estimate dust concentration and radiative forcing by dust more accurately, dust size distributions and dust single‐scattering albedo in the model should be a function of the source region, because dust concentration and the climate response to dust radiative forcing are sensitive to dust radiative parameters.