[{"issue":"11","author":[{"first_name":"Sara","last_name":"Shamekh","full_name":"Shamekh, Sara"},{"id":"f978ccb0-3f7f-11eb-b193-b0e2bd13182b","full_name":"Muller, Caroline J","orcid":"0000-0001-5836-5350","last_name":"Muller","first_name":"Caroline J"},{"full_name":"Duvel, Jean-Philippe","first_name":"Jean-Philippe","last_name":"Duvel"},{"first_name":"Fabio","last_name":"D’Andrea","full_name":"D’Andrea, Fabio"}],"publication":"Journal of the Atmospheric Sciences","_id":"9129","intvolume":"        77","month":"11","title":"How do ocean warm anomalies favor the aggregation of deep convective clouds?","date_created":"2021-02-15T14:07:30Z","article_processing_charge":"No","oa_version":"None","publication_status":"published","keyword":["Atmospheric Science"],"language":[{"iso":"eng"}],"quality_controlled":"1","page":"3733-3745","article_type":"original","publisher":"American Meteorological Society","type":"journal_article","date_published":"2020-11-01T00:00:00Z","year":"2020","citation":{"ieee":"S. Shamekh, C. J. Muller, J.-P. Duvel, and F. D’Andrea, “How do ocean warm anomalies favor the aggregation of deep convective clouds?,” <i>Journal of the Atmospheric Sciences</i>, vol. 77, no. 11. American Meteorological Society, pp. 3733–3745, 2020.","chicago":"Shamekh, Sara, Caroline J Muller, Jean-Philippe Duvel, and Fabio D’Andrea. “How Do Ocean Warm Anomalies Favor the Aggregation of Deep Convective Clouds?” <i>Journal of the Atmospheric Sciences</i>. American Meteorological Society, 2020. <a href=\"https://doi.org/10.1175/jas-d-18-0369.1\">https://doi.org/10.1175/jas-d-18-0369.1</a>.","apa":"Shamekh, S., Muller, C. J., Duvel, J.-P., &#38; D’Andrea, F. (2020). How do ocean warm anomalies favor the aggregation of deep convective clouds? <i>Journal of the Atmospheric Sciences</i>. American Meteorological Society. <a href=\"https://doi.org/10.1175/jas-d-18-0369.1\">https://doi.org/10.1175/jas-d-18-0369.1</a>","ama":"Shamekh S, Muller CJ, Duvel J-P, D’Andrea F. How do ocean warm anomalies favor the aggregation of deep convective clouds? <i>Journal of the Atmospheric Sciences</i>. 2020;77(11):3733-3745. doi:<a href=\"https://doi.org/10.1175/jas-d-18-0369.1\">10.1175/jas-d-18-0369.1</a>","ista":"Shamekh S, Muller CJ, Duvel J-P, D’Andrea F. 2020. How do ocean warm anomalies favor the aggregation of deep convective clouds? Journal of the Atmospheric Sciences. 77(11), 3733–3745.","short":"S. Shamekh, C.J. Muller, J.-P. Duvel, F. D’Andrea, Journal of the Atmospheric Sciences 77 (2020) 3733–3745.","mla":"Shamekh, Sara, et al. “How Do Ocean Warm Anomalies Favor the Aggregation of Deep Convective Clouds?” <i>Journal of the Atmospheric Sciences</i>, vol. 77, no. 11, American Meteorological Society, 2020, pp. 3733–45, doi:<a href=\"https://doi.org/10.1175/jas-d-18-0369.1\">10.1175/jas-d-18-0369.1</a>."},"date_updated":"2022-01-24T12:30:26Z","abstract":[{"text":"We investigate the role of a warm sea surface temperature (SST) anomaly (hot spot of typically 3 to 5 K) on the aggregation of convection using cloud-resolving simulations in a nonrotating framework. It is well known that SST gradients can spatially organize convection. Even with uniform SST, the spontaneous self-aggregation of convection is possible above a critical SST (here 295 K), arising mainly from radiative feedbacks. We investigate how a circular hot spot helps organize convection, and how self-aggregation feedbacks modulate this organization. The hot spot significantly accelerates aggregation, particularly for warmer/larger hot spots, and extends the range of SSTs for which aggregation occurs; however, at cold SST (290 K) the aggregated cluster disaggregates if we remove the hot spot. A large convective instability over the hot spot leads to stronger convection and generates a large-scale circulation which forces the subsidence drying outside the hot spot. Indeed, convection over the hot spot brings the atmosphere toward a warmer temperature. The warmer temperatures are imprinted over the whole domain by gravity waves and subsidence warming. The initial transient warming and concomitant subsidence drying suppress convection outside the hot spot, thus driving the aggregation. The hot-spot-induced large-scale circulation can enforce the aggregation even without radiative feedbacks for hot spots sufficiently large/warm. The strength of the large-scale circulation, which defines the speed of aggregation, is a function of the hot spot fractional area. At equilibrium, once the aggregation is well established, the moist convective region with upward midtropospheric motion, centered over the hot spot, has an area surprisingly independent of the hot spot size.","lang":"eng"}],"day":"01","publication_identifier":{"issn":["0022-4928","1520-0469"]},"doi":"10.1175/jas-d-18-0369.1","status":"public","user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","extern":"1","volume":77},{"date_updated":"2022-01-24T13:49:41Z","year":"2012","citation":{"ista":"Muller CJ, Held IM. 2012. Detailed investigation of the self-aggregation of convection in cloud-resolving simulations. Journal of the Atmospheric Sciences. 69(8), 2551–2565.","mla":"Muller, Caroline J., and Isaac M. Held. “Detailed Investigation of the Self-Aggregation of Convection in Cloud-Resolving Simulations.” <i>Journal of the Atmospheric Sciences</i>, vol. 69, no. 8, American Meteorological Society, 2012, pp. 2551–65, doi:<a href=\"https://doi.org/10.1175/jas-d-11-0257.1\">10.1175/jas-d-11-0257.1</a>.","short":"C.J. Muller, I.M. Held, Journal of the Atmospheric Sciences 69 (2012) 2551–2565.","chicago":"Muller, Caroline J, and Isaac M. Held. “Detailed Investigation of the Self-Aggregation of Convection in Cloud-Resolving Simulations.” <i>Journal of the Atmospheric Sciences</i>. American Meteorological Society, 2012. <a href=\"https://doi.org/10.1175/jas-d-11-0257.1\">https://doi.org/10.1175/jas-d-11-0257.1</a>.","ieee":"C. J. Muller and I. M. Held, “Detailed investigation of the self-aggregation of convection in cloud-resolving simulations,” <i>Journal of the Atmospheric Sciences</i>, vol. 69, no. 8. American Meteorological Society, pp. 2551–2565, 2012.","ama":"Muller CJ, Held IM. Detailed investigation of the self-aggregation of convection in cloud-resolving simulations. <i>Journal of the Atmospheric Sciences</i>. 2012;69(8):2551-2565. doi:<a href=\"https://doi.org/10.1175/jas-d-11-0257.1\">10.1175/jas-d-11-0257.1</a>","apa":"Muller, C. J., &#38; Held, I. M. (2012). Detailed investigation of the self-aggregation of convection in cloud-resolving simulations. <i>Journal of the Atmospheric Sciences</i>. American Meteorological Society. <a href=\"https://doi.org/10.1175/jas-d-11-0257.1\">https://doi.org/10.1175/jas-d-11-0257.1</a>"},"doi":"10.1175/jas-d-11-0257.1","day":"01","abstract":[{"text":"In models of radiative–convective equilibrium it is known that convection can spontaneously aggregate into one single localized moist region if the domain is large enough. The large changes in the mean climate state and radiative fluxes accompanying this self-aggregation raise questions as to what simulations at lower resolutions with parameterized convection, in similar homogeneous geometries, should be expected to produce to be considered successful in mimicking a cloud-resolving model.\r\nThe authors investigate this self-aggregation in a nonrotating, three-dimensional cloud-resolving model on a square domain without large-scale forcing. It is found that self-aggregation is sensitive not only to the domain size, but also to the horizontal resolution. With horizontally homogeneous initial conditions, convective aggregation only occurs on domains larger than about 200km and with resolutions coarser than about 2km in the model examined. The system exhibits hysteresis, so that with aggregated initial conditions, convection remains aggregated even at our finest resolution, 500m, as long as the domain is greater than 200–300km.\r\nThe sensitivity of self-aggregation to resolution and domain size in this model is due to the sensitivity of the distribution of low clouds to these two parameters. Indeed, the mechanism responsible for the aggregation of convection is the dynamical response to the longwave radiative cooling from low clouds. Strong longwave cooling near cloud top in dry regions forces downward motion, which by continuity generates inflow near cloud top and near-surface outflow from dry regions. This circulation results in the net export of moist static energy from regions with low moist static energy, yielding a positive feedback.","lang":"eng"}],"volume":69,"extern":"1","_id":"9142","author":[{"id":"f978ccb0-3f7f-11eb-b193-b0e2bd13182b","first_name":"Caroline J","last_name":"Muller","orcid":"0000-0001-5836-5350","full_name":"Muller, Caroline J"},{"first_name":"Isaac M.","last_name":"Held","full_name":"Held, Isaac M."}],"issue":"8","publication_status":"published","article_processing_charge":"No","date_created":"2021-02-15T14:39:03Z","title":"Detailed investigation of the self-aggregation of convection in cloud-resolving simulations","intvolume":"        69","page":"2551-2565","quality_controlled":"1","publisher":"American Meteorological Society","article_type":"original","date_published":"2012-08-01T00:00:00Z","type":"journal_article","publication_identifier":{"issn":["0022-4928","1520-0469"]},"oa":1,"main_file_link":[{"url":"https://doi.org/10.1175/JAS-D-11-0257.1","open_access":"1"}],"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","status":"public","publication":"Journal of the Atmospheric Sciences","oa_version":"Published Version","month":"08","language":[{"iso":"eng"}],"keyword":["Atmospheric Science"]}]