Regional and seasonal variations of the Twomey indirect effect as observed by the ATSR‐2 satellite instrument

Bulgin, Claire E.; Palmer, Paul I.; Thomas, G. E.; Arnold, C.; Campmany, E.; Carboni, Elisa; Grainger, R. G.; Poulsen, C.; Siddans, Richard; Lawrence, B. N.

doi:10.1029/2007gl031394

Cited by 36 publications

(36 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This effect has been already seen for weak volcanic eruptions over ocean (Gassó, 2008). The negative correlations shown in Bulgin et al (2008) between aerosol optical thickness and effective radius corroborate also this hypothesis. However, these results pertain only to oceanic regions, which are affected by continental aerosol outflows.…”

Section: Zonal Analysissupporting

confidence: 76%

See 1 more Smart Citation

Seven years of global retrieval of cloud properties using space-borne data of GOME

et al. 2012

View full text Add to dashboard Cite

show abstract

Section: Zonal Analysissupporting

confidence: 76%

“…However, these results pertain only to oceanic regions, which are affected by continental aerosol outflows. Note that the AOT signals in Bulgin et al (2008) and Thomas et al (2010) are derived from ATSR-2 measurements, therefore temporal and spatial co-registration with GOME are not an issue.…”

Section: Zonal Analysismentioning

confidence: 99%

Seven years of global retrieval of cloud properties using space-borne data of GOME

et al. 2012

View full text Add to dashboard Cite

show abstract

“…The retrievals have already been used to study ship tracks (Campmany et al, 2009;Sayer and Grainger, 2010) and study cloud-aerosol interactions (Bulgin et al, 2008). It is noted that, while the authors have applied the algorithm Table 1.…”

Section: A Poulsen Et Al: Cloud Retrieval Algorithmmentioning

confidence: 99%

Cloud retrievals from satellite data using optimal estimation: evaluation and application to ATSR

Poulsen

Siddans

Thomas³

et al. 2012

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. Clouds play an important role in balancing the Earth's radiation budget. Hence, it is vital that cloud climatologies are produced that quantify cloud macro and micro physical parameters and the associated uncertainty. In this paper, we present an algorithm ORAC (Oxford-RAL retrieval of Aerosol and Cloud) which is based on fitting a physically consistent cloud model to satellite observations simultaneously from the visible to the mid-infrared, thereby ensuring that the resulting cloud properties provide both a good representation of the short-wave and long-wave radiative effects of the observed cloud. The advantages of the optimal estimation method are that it enables rigorous error propagation and the inclusion of all measurements and any a priori information and associated errors in a rigorous mathematical framework. The algorithm provides a measure of the consistency between retrieval representation of cloud and satellite radiances. The cloud parameters retrieved are the cloud top pressure, cloud optical depth, cloud effective radius, cloud fraction and cloud phase.The algorithm can be applied to most visible/infrared satellite instruments. In this paper, we demonstrate the applicability to the Along-Track Scanning Radiometers ATSR-2 and AATSR. Examples of applying the algorithm to ATSR-2 flight data are presented and the sensitivity of the retrievals assessed, in particular the algorithm is evaluated for a number of simulated single-layer and multi-layer conditions. The algorithm was found to perform well for single-layer cloud except when the cloud was very thin; i.e., less than 1 optical depths. For the multi-layer cloud, the algorithm was robust except when the upper ice cloud layer is less than five optical depths. In these cases the retrieved cloud top pressure and cloud effective radius become a weighted average of the 2 layers. The sum of optical depth of multi-layer cloud is retrieved well until the cloud becomes thick, greater than 50 optical depths, where the cloud begins to saturate. The cost proved a good indicator of multi-layer scenarios. Both the retrieval cost and the error need to be considered together in order to evaluate the quality of the retrieval. This algorithm in the configuration described here has been applied to both ATSR-2 and AATSR visible and infrared measurements in the context of the GRAPE (Global Retrieval and cloud Product Evaluation) project to produce a 14 yr consistent record for climate research.

show abstract

“…The Reutter et al (2009) study was extended by Chang et al (2015), who took into account the evolution of the systems by considering the sensitivities on precipitation and ice phase, but was relatively limited in terms of representativeness because of the use of a 2-D model. Satellite studies (e.g., Bréon et al, 2002;Quaas et al, 2004;Bulgin et al, 2008) have an intrinsic limitation given the characteristics of the remote sensors. This kind of study usually deals with vertically integrated quantities and frequently focuses on oceanic regions because of the favorable surface contrast.…”

Section: Introductionmentioning

confidence: 99%

Sensitivities of Amazonian clouds to aerosols and updraft speed

et al. 2017

View full text Add to dashboard Cite

Abstract. The effects of aerosol particles and updraft speed on warm-phase cloud microphysical properties are studied in the Amazon region as part of the ACRIDICON-CHUVA experiment. Here we expand the sensitivity analysis usually found in the literature by concomitantly considering cloud evolution, putting the sensitivity quantifications into perspective in relation to in-cloud processing, and by considering the effects on droplet size distribution (DSD) shape. Our in situ aircraft measurements over the Amazon Basin cover a wide range of particle concentration and thermodynamic conditions, from the pristine regions over coastal and forested areas to the southern Amazon, which is highly polluted from biomass burning. The quantitative results show that particle concentration is the primary driver for the vertical profiles of effective diameter and droplet concentration in the warm phase of Amazonian convective clouds, while updraft speeds have a modulating role in the latter and in total condensed water. The cloud microphysical properties were found to be highly variable with altitude above cloud base, which we used as a proxy for cloud evolution since it is a measure of the time droplets that were subject to cloud processing. We show that DSD shape is crucial in understanding cloud sensitivities. The aerosol effect on DSD shape was found to vary with altitude, which can help models to better constrain the indirect aerosol effect on climate.

show abstract

Regional and seasonal variations of the Twomey indirect effect as observed by the ATSR‐2 satellite instrument

Cited by 36 publications

References 22 publications

Seven years of global retrieval of cloud properties using space-borne data of GOME

Seven years of global retrieval of cloud properties using space-borne data of GOME

Cloud retrievals from satellite data using optimal estimation: evaluation and application to ATSR

Sensitivities of Amazonian clouds to aerosols and updraft speed

Contact Info

Product

Resources

About