From Sugar to Flowers: A Transition of Shallow Cumulus Organization During ATOMIC

The Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) took place in January&ndash;February, 2020. It was designed to understand the relationship between shallow convection and the large-scale environment in the trade-wind regime. A Lagrangian large eddy simulation, following the trajectory of a boundary-layer airmass, can reproduce a transition of trade cumulus organization from &ldquo;sugar&rdquo; to &ldquo;flower&rdquo; clouds with cold pools, observed on February 2&ndash;3. The simulation is driven with reanalysis large-scale meteorology, and in-situ aerosol data from ATOMIC and its joint field study EUREC4A. During the transition, large-scale upward motion deepens the cloud layer. The total water path and optical depth increase, especially in the moist regions where flowers aggregate. This is due to mesoscale circulation that renders a net convergence of total water in the already moist and cloudy regions, strengthening the organization. An additional simulation shows that stronger large scale upward motion reinforces the mesoscale circulation and accelerates the organization process by strengthening the cloud-layer mesoscale buoyant turbulence kinetic energy production. &nbsp;</p

Public health in Thailand: Emerging focus on non‐communicable diseases

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86815/1/hpm1078.pd

Prevalence of chronic kidney disease using estimated glomerular filtration rate among diabetes patients attending a tertiary clinic in Botswana.

ObjectivesDiabetes mellitus (DM) is one of the most common contributors of chronic kidney disease (CKD). The epidemiology of CKD, a concern among patients with DM, has not been studied in Botswana. Consequently, the objective of this study was to estimate its prevalence among these patients in Botswana to provide future guidance to both government personnel and physicians.MethodsObservational cross-sectional study in a leading clinic in Botswana. Demographic and clinical data were obtained from patients through interviews and from their notes using a standard questionnaire. The study was conducted from July to October 2015. The estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet for Renal Disease equation. CKD was defined as an eGFR 2. Multivariable logistic regression analyses were performed to assess the associations between CKD and potential factors.ResultsThe mean age and duration of DM among study participants were 54.67 years (range 21-92 years) and 5.0 years, respectively. Over half, i.e. 213/370 (57.6%) and 232/370 (62.7%), had an average blood pressure greater than 140/90 mmHg and poor glycemic control (HbA1c > 7%), respectively. 31/370 patients (8.4%) had CKD. However, only 18/370 (4.9%) had a diagnosis of CKD documented in their charts. Age, level of education, and duration of diabetes were independently associated with CKD.ConclusionThe prevalence of CKD by estimated eGFR was low compared to most previous studies. However, half of patients with CKD are not documented resulting in the potential for prescription errors and drug toxicity. A substantial number of our patients had uncontrolled hypertension and poor glycemic control. Older age, low level of education and longer duration of DM were associated with CKD. There is a need to carry out prospective studies to determine the association and role of glycemic and blood pressure control in CKD causation among patients with DM in Botswana

Cloud Feedbacks in Limited-Area and Near-Global Cloud-Resolving Simulations of an Aquaplanet in SAM

Thesis (Master's)--University of Washington, 2017-03Global climate models (GCMs) with conventional cumulus parameterization produce a wide spread in cloud feedbacks due to uncertainty from low clouds. Cloud-resolving model (CRM) and large-eddy simulations (LES) can be used to explicitly calculate individual clouds and study cloud-climate responses. This study concentrates on feedbacks of different cloud regimes in ocean-only CRMs of fixed sea-surface temperature (SST), both with small-area and near-global domain sizes. The first part of the thesis focuses on improvement of stratocumulus simulations in a coarse-resolution CRM with a grid spacing of 250 x 250 x 20 m. Three approaches were implemented to help the model maintain stratocumulus liquid water path, but only one is found to be helpful: turning off the subgrid scalar diffusivity except at the surface. The model setup has been further tested for its predictability of cloud feedbacks in various dynamical regimes. The CRM shows some biases in simulating the deep convective clouds and shallow cumulus since the domain size is too small. But it is able to simulate stratocumulus and stratocumulus under cumulus well. The second part focuses on cloud feedbacks in a near-global aquaplanet CRM with fixed meridionally-varying SST, under three climate perturbations: a uniform 4 K SST increase, CO2 quadrupling, and both combined. The CRM has a horizontal resolution of 4 km with no cumulus parameterization. Its domain is a zonally periodic 20480 km-long tropical channel, spanning 46◦S-N with rigid walls. It produces plausible mean distributions of clouds, rainfall and winds. After spin-up, 80 days are analyzed for the control and increased-SST simulations, and 40 days for those with quadrupled CO2. The Intertropical Convergence Zone width and tropical cloud cover are not strongly affected by SST warming or CO2 increase, except for the expected upward shift in high clouds with warming, but both perturbations weaken the Hadley circulation. Increased SST induces a statistically significant increase in subtropical low cloud fraction and in-cloud liquid water content but decreases midlatitude cloud, yielding slightly positive domain-mean shortwave cloud feedbacks. CO2 quadrupling causes a slight shallowing and a statistically insignificant reduction of subtropical low cloud fraction. Warming-induced low cloud changes are strongly correlated with changes in estimated inversion strength, which increases modestly in the subtropics but decreases in the midlatitudes due to poleward jet shifts. Enhanced clear-sky boundary-layer radiative cooling in the warmer climate accompanies the robust subtropical low cloud increase. The probability density function of column relative humidity and precipitation rate across the tropics and subtropics is compared between the control and the increased-SST simulations as a measure of convective aggregation and precipitation extreme, respectively. It shows no evidence of increased aggregation in the warmer climate, while precipitation extreme increases approximately at the Clausius-Clapeyron rate

A Study of Multiscale Processes in Near-Global Aquaplanet Cloud-Resolving Models: From Shallow Cumulus Cloud Feedbacks to Tropical Cyclogenesis Predictability

Thesis (Ph.D.)--University of Washington, 2019A near-global aquaplanet cloud-resolving models (NGAqua) has been used to study the responses of clouds and circulations to 4 K sea-surface temperature (SST) warming, CO2 quadrupling, and both combined. NGAqua spans a large tropical channel domain, with 4 km horizontal resolution, latitudinally dependent SST, and no cumulus parameterization. Prior work showed that its coarsely-resolved shallow cumulus increases with warming. It was suggested that with warmer SST, the moister boundary layer is destabilized by more clear-sky radiative cooling, driving more cumulus convection. Limited-area cloud-resolving model (CRM) simulations are used to reproduce and under- stand negative subtropical shallow cumulus cloud feedbacks in NGAqua. A small doubly- periodic version of the same CRM is configured to analyze this low cloud increase in a simpler context. It is driven by steady thermodynamic and advective forcing profiles averaged over the driest subtropical column humidity quartile of NGAqua. Sensitivity studies separate effects of radiative cooling and free-tropospheric relative humidity changes from other as- pects of NGAqua’s warmer climate. Enhanced clear-sky radiative cooling explains most of the cloud increase due to SST warming, regardless of CRM model resolution and advection scheme. Furthermore, the analysis of the BL liquid virtual static energy suggests that if shallow cumulus clouds were deeper and rained more, warmer SST may result in increased precipitation rather than increased cloud cover. Topical cyclogenesis is a multiscale process that involves interactions between large-scale circulations and small-scale tropical convection. NGAqua simulations can produce tropical cyclones (TCs) when the SST distribution is shifted northward such that its maximum is off-equatorial. In this case, the TCs spin up spontaneously from the northern edge of the Intertropical Convergence Zone (ITCZ). The large-scale flows provide necessary conditions for barotropic instability and predetermine where the pre-TC vortices will be found. The predictability of this process is up to ten days. The ITCZ is also a rich source for atmo- spheric column-integrated moisture, which is important of the growth of tropical convection, a process that is less predictable. A Lagrangian-framework analysis shows that vertical stretching of absolute vorticity associated with moist convective updrafts contributes posi- tively to the absolute vorticity tendency of a TC. A compositing analysis suggests that the vorticity stretching is crucial for the spin up. But pre-TC vortices do not develop into TCs if they are situated over regions of strong horizontal moisture gradients, because the vertical stretching does not align with the centers of the cyclonic vorticity anomalies

Supporting data for Narenpitak and Bretherton (2018): Understanding Negative Subtropical Shallow Cumulus Cloud Feedbacks in a Near-Global Aquaplanet Model Using Limited-Area Cloud-Resolving Simulations

Author: Pornampai Narenpitak ([email protected]). This archive includes data used to generate the figures and tables in: Pornampai Narenpitak, and Christopher S. Bretherton, 2018. Understanding Negative Subtropical Shallow Cumulus Cloud Feedbacks in a Near-Global Aquaplanet Model Using Limited-Area Cloud-Resolving Simulations. Submitted to the Journal of Advances in Modeling Earth Systems. See the "Supporting_data_description.pdf" file for a listing of files in the .zip archive and a description of their use.The data included here should enable the reproduction of the tables and plots in Narenpitak et al. (2018, J. Adv. Model. Earth Syst., submitted) and its Supporting Information, with the exception of two figures that are 3D images of the cloud fields and a schematic diagram. The dataset uploaded are (1) the domain-mean model outputs of the limited-area version of the System of Atmospheric Modeling (LASAM) simulations and (2) the quartile-binned statistics of the subtropics in near-global aquaplenet cloud-resolving simulations (NGAqua). The full 3D outputs are not included because of the large file size. Domain-mean outputs of LASAM simulations beyond that needed for the figures in the paper are included, so that the interested user may look at other cloud properties discussed in the paper using the data here.DOE grant DE-SC0012451. Scholarship from the Thai Ministry of Science and Technology

Supporting data for Narenpitak, Bretherton and Khairoutdinov (2020): The Role of Multiscale Interaction in Tropical Cyclogenesis and Its Predictability in Near-Global Aquaplanet Cloud-Resolving Simulations

Author: Pornampai Narenpitak ([email protected]). This archive includes data used to perform analyses on tropical cyclogenesis and its predictability in: Pornampai Narenpitak, Christopher S. Bretherton, and Marat F. Khairoutdinov, 2020. The Role of Multiscale Interaction In Tropical Cyclogenesis and Its Predictability in Near-Global Aquaplanet Cloud-Resolving Simulations. Submitted to the Journal of Atmospheric Sciences. See the "Supporting_data_description.pdf" file for a listing of files in the .zip archive and a description of their use.The data included here should enable the reproduction of major analyses in Narenpitak et al. (2020, Journal of Atmospheric Sciences, submitted) about tropical cyclogenesis and its predictability. Since the near-global aquaplenet cloud-resolving simulations (NGAqua) produce large model outputs, it is impractical to archive all of the datasets. Therefore, the author archived selected tropical cyclone cases that are discussed in detail in the manuscript.The research projects were made possible by funding from Department of Energy grant DE-SC0012451, the National Science Foundation Science and Technology Center for Multi-Scale Modeling of Atmospheric Processes (CMMAP) under grant ATM-0425247, and by a scholarship from Thailand's Ministry of Higher Education, Science, Research and Innovation. Computational resources were provided by the Extreme Science and Engineering Discovery Environment (XSEDE) grant OCI-1053575

A comparison between 12 versus 20 weeks of trimethoprim-sulfamethoxazole as oral eradication treatment for melioidosis: an open-label, pragmatic, multicenter, non-inferiority, randomized controlled trial

Background Treatment of melioidosis comprises intravenous drugs for at least 10 days, followed by oral trimethoprim-sulfamethoxazole (TMP-SMX) for 12 to 20 weeks. Oral TMP-SMX is recommended for 12 weeks in Australia and 20 weeks in Thailand. Methods For this open-label, pragmatic, multicenter, noninferiority, randomized controlled trial, we enrolled patients with culture-confirmed melioidosis who had received oral eradication treatment for 12 weeks and had no clinical evidence of active melioidosis. We randomly assigned patients to stop treatment (12-week regimen) or continue treatment for another 8 weeks (20-week regimen). The primary end point was culture-confirmed recurrent melioidosis within 1 year after enrollment. The noninferiority margin was a hazard ratio (HR) of 2.0. The secondary composite end point, combining overall recurrent melioidosis and mortality, was assessed post hoc. Results We enrolled 658 patients: 322 to the 12-week regimen and 336 to the 20-week regimen. There were 5 patients (2%) in the 12-week regimen and 2 patients (1%) in the 20-week regimen who developed culture-confirmed recurrent melioidosis (HR, 2.66; 95% confidence interval [CI], .52–13.69). The criterion for noninferiority of the primary event was not met (1-sided P = .37). However, all-cause mortality was significantly lower in the 12-week regimen group than in the 20-week regimen group (1 [.3%] vs 11 [3%], respectively; HR, 0.10; 95% CI, .01–.74). The criterion for noninferiority of the secondary composite end point, combining overall recurrent melioidosis and mortality, was met (1-sided P = .022). Conclusions Based on the lower total mortality and noninferiority of the secondary composite end point observed, we recommend the 12-week regimen of TMP-SMX for oral eradication treatment of melioidosis. Clinical Trials Registration NCT01420341.</p