ALBERT

Description: To better understand and characterize current uncertainties in the important observational constraint of climate models of aerosol optical depth (AOD), we evaluate and intercompare 14 satellite products, representing nine different retrieval algorithm families using observations from five different sensors on six different platforms. The satellite products (super-observations consisting of 1∘×1∘ daily aggregated retrievals drawn from the years 2006, 2008 and 2010) are evaluated with AErosol RObotic NETwork (AERONET) and Maritime Aerosol Network (MAN) data. Results show that different products exhibit different regionally varying biases (both under- and overestimates) that may reach ±50 %, although a typical bias would be 15 %–25 % (depending on the product). In addition to these biases, the products exhibit random errors that can be 1.6 to 3 times as large. Most products show similar performance, although there are a few exceptions with either larger biases or larger random errors. The intercomparison of satellite products extends this analysis and provides spatial context to it. In particular, we show that aggregated satellite AOD agrees much better than the spatial coverage (often driven by cloud masks) within the 1∘×1∘ grid cells. Up to ∼50 % of the difference between satellite AOD is attributed to cloud contamination. The diversity in AOD products shows clear spatial patterns and varies from 10 % (parts of the ocean) to 100 % (central Asia and Australia). More importantly, we show that the diversity may be used as an indication of AOD uncertainty, at least for the better performing products. This provides modellers with a global map of expected AOD uncertainty in satellite products, allows assessment of products away from AERONET sites, can provide guidance for future AERONET locations and offers suggestions for product improvements. We account for statistical and sampling noise in our analyses. Sampling noise, variations due to the evaluation of different subsets of the data, causes important changes in error metrics. The consequences of this noise term for product evaluation are discussed.

Description: Estimates of the direct radiative effect (DRE) from absorbing smoke aerosols over the southeast Atlantic Ocean (SAO) require simulation of the microphysical and optical properties of stratocumulus clouds as well as of the altitude and shortwave (SW) optical properties of biomass burning aerosols (BBAs). In this study, we take advantage of the large number of observations acquired during the ObseRvations of Aerosols above Clouds and their intEractionS (ORACLES-2016) and Layered Atlantic Smoke Interactions with Clouds (LASIC) projects during September 2016 and compare them with datasets from the ALADIN-Climate (Aire Limitée Adaptation dynamique Développement InterNational) regional model. The model provides a good representation of the liquid water path but the low cloud fraction is underestimated compared to satellite data. The modeled total-column smoke aerosol optical depth (AOD) and above-cloud AOD are consistent (∼0.7 over continental sources and ∼0.3 over the SAO at 550 nm) with the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2), Ozone Monitoring Instrument (OMI) or Moderate Resolution Imaging Spectroradiometer (MODIS) data. The simulations indicate smoke transport over the SAO occurs mainly between 2 and 4 km, consistent with surface and aircraft lidar observations. The BBA single scattering albedo is slightly overestimated compared to the Aerosol Robotic Network (AERONET) and more significantly when compared to Ascension Island surface observations. The difference could be due to the absence of internal mixing treatment in the ALADIN-Climate model. The SSA overestimate leads to an underestimation of the simulated SW radiative heating compared to ORACLES data. ALADIN-Climate simulates a positive (monthly mean) SW DRE of about +6 W m−2 over the SAO (20∘ S–10∘ N and 10∘ W–20∘ E) at the top of the atmosphere and in all-sky conditions. Over the continent, the presence of BBA is shown to significantly decrease the net surface SW flux, through direct and semi-direct effects, which is compensated by a decrease (monthly mean) in sensible heat fluxes (−25 W m−2) and surface land temperature (−1.5 ∘C) over Angola, Zambia and the Democratic Republic of the Congo, notably. The surface cooling and the lower tropospheric heating decrease the continental planetary boundary layer height by about ∼200 m.

Description: Estimates of the direct radiative forcing (DRF) from absorbing smoke aerosols over the Southeast Atlantic Ocean (SAO) requires simulation of the microphysical and optical properties of stratocumulus clouds (Sc) as well as of the altitude and shortwave (SW) optical properties of biomass burning aerosols (BBA). In this study, we take advantage of the large number of observations acquired during the ORACLES-2016 and LASIC projects during September 2016 and compare them with datasets from the ALADIN-Climate regional model. The model provides a good representation of the liquid water path (LWP) but the low cloud fraction (LCF) is underestimated compared to satellite data. The modeled total column smoke aerosol optical depth (AOD) and Above Cloud AOD (ACAOD) are consistent (~ 0.7 over continental sources and ~ 0.3 over SAO at 550 nm) with MERRA2, OMI or MODIS data. The simulations indicate smoke transport over SAO occurs mainly between 2 and 4 km, consistent with surface and aircraft lidar observations. The BBA single scattering albedo (SSA) is slightly overestimated compared to AERONET, and more significantly when compared to Ascension Island surface observations. The difference could be due to the absence of internal mixing treatment in the ALADIN-Climate model. The SSA overestimate leads to underestimate the simulated SW radiative heating compared to ORACLES data. For September 2016, ALADIN-Climate simulates a positive (monthly mean) SW DRF of about +6 W m−2 over SAO (20° S–10° N and 10° W–20° E) at the top of the atmosphere (TOA) and in all-sky conditions. Over the continent, the presence of BBA is shown to significantly decrease the net surface SW flux, through direct and semi-direct effects, which is compensated by a decrease (monthly mean) in sensible heat fluxes (−25 W/m−2) and surface land temperature (−1.5 °C) over Angola, Zambia and Congo notably. The surface cooling and the lower tropospheric heating tends to decrease the continental planetary boundary layer (PBL) height by about ~ 200 m.

Description: BACKGROUND Patients with newly diagnosed acute lymphoblastic leukemia (ALL) are at increased risk of infection. While previously published guidelines recommend primary antifungal prophylaxis in patients with T-cell ALL, we sought to determine the pattern of invasive fungal disease (IFI) at our center so as to assess risk factors for IFI, beyond the diagnosis of T-ALL, with the administration of dexamethasone and an anthracycline during induction. The current practice at Children's Health Children's Medical Center Dallas is to provide primary antifungal prophylaxis with micafungin during induction therapy for hospitalized patients with T-cell ALL and those with Down Syndrome. Additionally, we recently decided to provide primary antifungal prophylaxis to patients with HR B-ALL with hyperglycemia who remain hospitalized during induction. The primary objective of this study was to capture the institution-specific five-year incidence of IFI prior to the start of delayed intensification (DI) phase chemotherapy among pediatric patients with ALL. Secondary objectives were to identify potential IFI risk factors specifically amongst pediatric patients with HR ALL. METHODS This retrospective chart review included patients younger than 21 years with newly diagnosed ALL between July 1, 2014 and June 30, 2019. Patients with secondary leukemia, infantile leukemia, or those receiving treatment for a fungal infection at presentation were excluded. The primary outcome was the development of probable or proven IFI, as defined by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria, prior to the start of the DI phase of therapy. Statistical methods included Chi-square test, t-test, and Wilcoxon Rank Sum test, as appropriate to the variable's level of measurement and distribution. Time series analyses were used to assess overall and seasonal trends of IFI incidence over the study period. RESULTS Of 220 included patients, there were 13 cases of IFI diagnosed during the induction and consolidation phases of therapy during the five-year period. IFI occurred in 15.3% of the HR group (11/72), 5.9% of the T-cell ALL group (1/17), and 0.8% of the standard risk (SR) group (1/131). Among individuals with HR ALL, the majority of cases occurred in the absence of primary antifungal prophylaxis (90.9%). The most common sites of IFI included the lungs (n=6) and sinuses (n=4). Implicated fungal pathogens included Aspergillus, Candida, Curvularia, Exserohilum, and Bipolaris. Univariate analysis of the potential IFI risk factors in HR ALL patients did not identify any significant differences between those patients that did or did not develop IFI, with respect to pre-existing comorbidities, body mass index, laboratory results at diagnosis, or hospital exposures during induction including length of stay, intensive care admissions, and receipt of systemic antibiotics (Table). Race and ethnicity was significantly different likely due to the skewed distribution of IFI among patients who identified as Asian (p = 0.03; 8/8 identified as Asian and did not develop IFI). With respect to seasonality of ALL diagnosis, the percent of patients in each group (winter, spring, summer, and fall) that developed IFI were 7.4%, 18.2%, 20%, and 31.2%, respectively. However, time series analysis did not show an association between seasonality of diagnosis and development of IFI (p=0.89). During the induction phase of therapy, hyperglycemia, defined as blood glucose 140-200 mg/dL for ≥ 2 days or 〉200 mg/dL for 1 day, was present in 100% of the HR patients that developed IFI and 74% of the HR patients that did not develop IFI (p=0.12). CONCLUSION In this pediatric population, patients with HR B-ALL developed more fungal infections during the early phases of therapy then those with SR disease (15.6% versus 0.8%). In analysis of potential risk factors, there were no significant differences between HR ALL groups that did or did not develop IFI. Larger-scale studies are needed in order to identify potential risk factors that will guide decisions on the routine use of primary antifungal prophylaxis in patients with HR ALL during induction therapy. Disclosures No relevant conflicts of interest to declare. OffLabel Disclosure: Micafungin use for primary antifungal prophylaxis during induction phase of therapy.

Description: In Asian monsoon countries, such as China and India, human health and safety problems caused by air pollution are becoming increasingly serious, due to the increased loading of atmospheric pollutants from waste gas emissions and from rising energy demand associated with the rapid pace of industrialization and modernization. Meanwhile, uneven distribution of monsoon rain associated with flash floods or prolonged drought, has caused major loss of human life and damage to crops and.property with devastating societal impacts. Historically, air-pollution and monsoons research are treated as separate problems. However recent studies have suggested that the two problems may be intrinsically linked and need to be studied jointly. Fundamentally, aerosols can affect precipitation through radiative effects cif suspended particles in the atmosphere (direct effect) and/or by interfering and changing: the cloud and precipitation formation processes (indirect effect). Based on their optical properties, aerosols can be classified into two types.: those that absorb solar radiation, and those that do not. Both types of aerosols scatter sunlight and reduce the amount of solar radiation from reaching the Earth's surface, causing it to cool. The surface cooling increases atmospheric stability and reduces convection potential, Absorbing aerosols, however, in addition to cooling the surface, can heat the atmosphere. The heating of the atmosphere may reduce the amount of low clouds by increased evaporation in cloud drops. The heating, however, may induce rising motion, enhance low-level moisture, convergence and, hence, increases rainfall, The latent heating from enhanced rainfall may excite feedback processes in the large-scale circulation, further amplify.the initial response to aerosol heating and producing more rain. Additionally, aerosols can increase the concentration of cloud condensation nuclei (CCN), increase cloud amount and decrease coalescence and collision rates, leading to reduced precipitation. However, in the presence of increasing moist and warm air, the reduced coalescence/collision may lead to supercooled drops at higher altitudes where ice precipitation falls and melts. The latent heat release from freezing aloft and melting below implies greater upward heat transport in polluted clouds and invigorate deep convection. In this way, aerosols may lead to increased local convection. Hence, depending on the ambient large-scale conditions and dynamical feedback processes, aerosols' effect on precipitation can be positive, negative or mixed. In the Asian monsoon and adjacent regions, the aerosol forcing and responses of the water cycle are even more complex, Both direct and indirect effects may take place locally and simultaneously, interacting with each other. in addition to local effects, monsoon rainfall may be affected by aerosols transported from other regions and intensified through large-scale circulation and moisture feedback. Thus, dust transported by the large-scale circulation from the adjacent deserts to northern India may affect rainfall over the Bay of Bengal; sulphate and black carbon front industrial pollution in central, southern China and northern India may affect the rainfall regime over the Korean peninsula and Japan; organic and black carbon front biomass burning from Indo-China may modulate the pre-monsoon rainfall regime over southern China and coastal regions, contributing to variability in differential heating and cooling of the atmosphere and to the land-sea thermal contrast. During the pre-monsoon season and monsoon breaks, it has been suggested that radiative forcing by absorbing aerosols have nearly the same order of magnitude as the forcing due to latent heating from convection and surface fluxes. The magnitude of the total aerosol radiative cooling due to sulphates and soot is of the order of 20-40 W/m2 over the Asian monsoon land region in the pre-monsoon season, compared to about 1-2 W/m2 for global warng. However, the combined forcing at the surface and in the atmosphere, including all species. if aerosols, and details of aerosol mixing, and impacts on the energy and water cycles in the monsoon land regions, are not well known.

Description: Current assessment of aerosol radiative effect is hindered by our incomplete knowledge of aerosol optical properties, especially absorption, and our current inability to quantify physical and microphysical processes. In this research, we investigate direct aerosol radiative effect over heavy aerosol loading areas (e.g., Indo-Gangetic Plains, South/East Asia) and its feedbacks on the South Asian climate during the pre-monsoon season (March-June) using the Purdue Regional Climate Model (PRCM) with prescribed aerosol data derived by the NASA Goddard Earth Observing System Model (GEOS-5). Our modeling domain covers South and East Asia (60-140E and 0-50N) with spatial resolutions of 45 km in horizontal and 28 layers in vertical. The model is integrated from 15 February to 30 June 2008 continuously without nudging (i.e., only forced by initial/boundary conditions). Two numerical experiments are conducted with and without the aerosol-radiation effects. Both simulations are successful in reproducing the synoptic patterns on seasonal-to-interannual time scales and capturing a pre-monsoon feature of the northward rainfall propagation over Indian region in early June which shown in Tropical Rainfall Measuring Mission (TRMM) observation. Preliminary result suggests aerosol-radiation interactions mainly alter surface-atmosphere energetics and further result in an adjustment of the vertical temperature distribution in lower atmosphere (below 700 hPa). The modifications of temperature and associated rainfall and circulation feedbacks on the regional climate will be discussed in the presentation.

Description: Biomass burning has been a regular practice for land clearing and land conversion in many countries, especially those in Africa, South America, and Southeast Asia. However, the unique climatology of Southeast Asia is very different than that of Africa and South America, such that large-scale biomass burning causes smoke to interact extensively with clouds during the peak-burning season of March to April. Significant global sources of greenhouse gases (e.g., CO2, CH4), chemically active gases (e.g., NO, CO, HC, CH3Br), and atmospheric aerosols are produced by biomass burning processes. These gases influence the Earth-atmosphere system, impacting both global climate and tropospheric chemistry. Some aerosols can serve as cloud condensation nuclei, which play an important role in determining cloud lifetime and precipitation, hence, altering the earth's radiation and water budget. Biomass burning also affects the biogeochemical cycling of nitrogen and carbon compounds from the soil to the atmosphere; the hydrological cycle (i.e., run off and evaporation); land surface reflectivity and emissivity; as well as ecosystem biodiversity and stability. Analyses from satellite measurements reveal that smoke is frequently present solar (emitted thermal) radiation from clouds due to smoke aerosols can be reduced (enhanced) by as much as 100 (20) W/sq m over the month of March 2000. In addition, the reduction in cloud spectral reflectance at 670 run is large enough to lead to significant errors in retrieving cloud properties (e.g., optical thickness and effective radius) from satellite measurements. The fresh water distribution in this region is highly dependent on monsoon rainfall; in fact, the predictability of the tropical climate system is much reduced during the boreal spring. Estimating the burning fuel (e.g., bark, branches, and wood), an important part of studying regional carbon cycle, may rely on utilizing a wide range of distinctive spectral features in the shortwave and longwave regions. Therefore, to accurately assess the impact of smoke aerosols in this region requires continuous observations from satellites, aircraft, networks of ground-based instruments and dedicated field experiments. A new initiative will be proposed and discussed.