Aerosol Effects on Microstructure and Intensity of Tropical Cyclones

Rosenfeld, Daniel; Woodley, William L.; Хаин, А.; Cotton, William R.; Carrió, G. G.; Ginis, Isaac; Golden, Joseph

doi:10.1175/bams-d-11-00147.1

Cited by 134 publications

(111 citation statements)

References 77 publications

(58 reference statements)

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“…Their absence also has limited our ability to validate the hypothesized impacts of added aerosols on a large range of phenomena, including (i) maintaining full cloud cover in marine stratocumulus, thus incurring a strong cooling effect on the climate system (5); (ii) suppressing precipitation from shallow clouds (6-8); (iii) invigorating the convection in deep tropical clouds (9); (iv) enhancing cloud electrification (10,11); (v) intensifying severe convective storms to produce more large hail and tornadoes (12); and (vi) decreasing the intensity of tropical cyclones (13). In addition to their intrinsic importance, these aerosol effects could induce radiative effects that change Earth's energy budget in a significant way (1).…”

Section: Need For Global Measurements Of Cloud Base Updrafts and Ccn(s)mentioning

confidence: 99%

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

Rosenfeld

Zheng

Hashimshoni

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

118

130

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Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (W b ). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and W b of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by W b and the satellite-retrieved cloud base drop concentrations (N db ), which is the same as CCN(S). Validation against ground-based CCN instruments at Oklahoma, at Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25°restricts the satellite coverage to ∼25% of the world area in a single day. (1) states that the uncertainty in aerosol/cloud interactions dominates the uncertainty about the degree of influence that human activities have on climate. Because clouds form in ascending air currents, whereas cloud droplets nucleate on aerosols that serve as cloud condensation nuclei (CCN), we need accurate measurements of both updrafts and CCN supersaturation (S) spectra before we can disentangle aerosol effects on cloud radiative forcing (CRF) from dynamical effects. Need for Global Measurements of Cloud Base Updrafts and CCN(S)Tackling the global change problems as identified by the IPCC requires that these quantities be measured on a global scale. However, satellites have not been able to measure updraft speed of the air that forms the clouds or the concentrations of aerosols that are capable of forming cloud drops, which are ingested into the clouds as they grow. Lack of such fundamental quantities has greatly hindered our capability of disentangling the effects of meteorology and anthropogenic aerosol emissions on cloud properties (2). This situation is starting to change with our recently developed methodology to retrieve updrafts at cloud base (3, 4) using the Visible/Infrared Imager Radiometer Suite (VIIRS) instrument onboard the Suomi National Polar-orbiting Partnership (NPP) satellite. This satellite is sun-synchronous, with an overpass time near 13:30 solar time.Missing such fundamental quantities as CCN(S) and cloud base updraft W b has been preventing us from disentangling the effects of aerosols from atmospheric dynamics (i.e., meteorology). Their absence also has limited our ability to validate the hypothesized impacts of added aerosols on a large range of phenomena, including (i) maintaining full cloud cover in marine stratocumulus, thus incurring a str...

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Section: Need For Global Measurements Of Cloud Base Updrafts and Ccn(s)mentioning

confidence: 99%

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

Rosenfeld

Zheng

Hashimshoni

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

118

130

View full text Add to dashboard Cite

show abstract

“…In particular, the aerosols have an indirect effect by serving as cloud condensation nuclei, and their interaction with the microphysics and dynamics of deep convective clouds (DCCs) may modify the cloud structure and redistribute latent heating (6), leading to an enhanced precipitation efficiency (7)(8)(9)(10)(11)(12), invigorated convection strength (13)(14)(15), and intensified lightning activities (16)(17)(18). At this time, the indirect radiative forcing of anthropogenic aerosols represents the least-understood component in the forcing of climate change (19,20).…”

mentioning

confidence: 99%

Assessing the effects of anthropogenic aerosols on Pacific storm track using a multiscale global climate model

Wang

Zhang

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

139

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Atmospheric aerosols affect weather and global general circulation by modifying cloud and precipitation processes, but the magnitude of cloud adjustment by aerosols remains poorly quantified and represents the largest uncertainty in estimated forcing of climate change. Here we assess the effects of anthropogenic aerosols on the Pacific storm track, using a multiscale global aerosol-climate model (GCM). Simulations of two aerosol scenarios corresponding to the present day and preindustrial conditions reveal long-range transport of anthropogenic aerosols across the north Pacific and large resulting changes in the aerosol optical depth, cloud droplet number concentration, and cloud and ice water paths. Shortwave and longwave cloud radiative forcing at the top of atmosphere are changed by −2.5 and +1.3 W m −2 , respectively, by emission changes from preindustrial to present day, and an increased cloud top height indicates invigorated midlatitude cyclones. The overall increased precipitation and poleward heat transport reflect intensification of the Pacific storm track by anthropogenic aerosols. Hence, this work provides, for the first time to the authors' knowledge, a global perspective of the effects of Asian pollution outflows from GCMs. Furthermore, our results suggest that the multiscale modeling framework is essential in producing the aerosol invigoration effect of deep convective clouds on a global scale.aerosol-cloud-climate interaction | convective storms, cloud invigoration A tmospheric aerosols, formed from both natural and anthropogenic sources (1, 2), affect the Earth's energy budget directly, by scattering or absorbing solar radiation, and indirectly, by altering cloud microphysical characteristics and regulating the hydrological cycle (3-5). In particular, the aerosols have an indirect effect by serving as cloud condensation nuclei, and their interaction with the microphysics and dynamics of deep convective clouds (DCCs) may modify the cloud structure and redistribute latent heating (6), leading to an enhanced precipitation efficiency (7-12), invigorated convection strength (13-15), and intensified lightning activities (16)(17)(18). At this time, the indirect radiative forcing of anthropogenic aerosols represents the least-understood component in the forcing of climate change (19,20).Increasing levels of particulate matter (PM) pollutants from the Asian continent and their associated outflows have raised considerable concern because of their potential effects on regional climate and global atmospheric circulation (21-23). Intense emissions of anthropogenic aerosols and their long-range transport from Asia are clearly documented by satellite and in situ measurements (21,22). Zhang and colleagues (23) first suggested that Asian pollution likely accounts for a climatically increased DCC amount over the north Pacific on the basis of long-term analysis of cloud measurements from the International Satellite Cloud Climatology Project and high-resolution infrared sounder. In addition, a trend of increasing win...

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“…The aerosolinduced vertical growth and the consequent expansion of the anvils into cirrus was observed (Koren et al, 2010) and simulated (Fan et al, 2012) to inflict large positive radiative forcing, in contrast to the strong negative forcing that is caused by the aerosol effect on shallow clouds, at least in heavily drizzling marine stratocumulus (e.g., Albrecht, 1989). In the context of tropical cyclones, the invigoration of clouds at the periphery of the storms occurs at the expense of a reduction in the amount of air converging into the storm center, hence reducing the maximum wind speeds (Rosenfeld et al, 2012b and references therein). The aerosols were found even to affect the potential of deep convective clouds to produce large hail and tornadoes, where clouds with added pollution aerosols become potentially more damaging (Rosenfeld and Bell, 2011 and references therein).…”

Section: Ways By Which Aerosols Affect Cloud Microphysical Precipitamentioning

confidence: 95%

The scientific basis for a satellite mission to retrieve CCN concentrations and their impacts on convective clouds

et al. 2012

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Abstract. The cloud-mediated aerosol radiative forcing is widely recognized as the main source of uncertainty in our knowledge of the anthropogenic forcing on climate. The current challenges for improving our understanding are (1) global measurements of cloud condensation nuclei (CCN) in the cloudy boundary layer from space, and (2) disentangling the effects of aerosols from the thermodynamic and meteorological effects on the clouds. Here, we present a new conceptual framework to help us overcome these two challenges, using relatively simple passive satellite measurements in the visible and infared (IR). The idea is to use the clouds themselves as natural CCN chambers by retrieving simultaneously the number of activated aerosols at cloud base, N a , and the cloud base updraft speed. The N a is obtained by analyzing the distribution of cloud drop effective radius in convective elements as a function of distance above cloud base. The cloud base updraft velocities are estimated by double stereoscopic viewing and tracking of the evolution of cloud surface features just above cloud base. In order to resolve the vertical dimension of the clouds, the field of view will be 100 m for the microphysical retrievals, and 50 m for the stereoscopic measurements. The viewing geometry will be eastward and 30 degrees off nadir, with the Sun in the back at 30 degrees off zenith westward, requiring a Sun-synchronous orbit at 14 LST. Measuring simultaneously the thermodynamic environment, the vertical motions of the clouds, their microstructure and the CCN concentration will allow separating the dynamics from the CCN effects. This concept is being applied in the proposed satellite mission named Clouds, Hazards and Aerosols Survey for Earth Researchers (CHASER).

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Aerosol Effects on Microstructure and Intensity of Tropical Cyclones

Cited by 134 publications

References 77 publications

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

Satellite retrieval of cloud condensation nuclei concentrations by using clouds as CCN chambers

Assessing the effects of anthropogenic aerosols on Pacific storm track using a multiscale global climate model

The scientific basis for a satellite mission to retrieve CCN concentrations and their impacts on convective clouds

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