Tropospheric ozone and aerosols measured by airborne lidar during the 1988 Arctic boundary layer experiment

Ozone (O3) and aerosol distributions were measured from an aircraft using a differential absorption lidar (DIAL) system as part of the 1988 NASA Global Tropospheric Experiment - Arctic Boundary Layer Experiment (ABLE-3A) to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during the summer. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere. Several cases of continental polar air masses were examined during the experiment. The aerosol scattering associated with these air masses was very low, and the atmospheric distribution of aerosols was quite homogeneous for those air masses that had been transported over the ice for greater than or = 3 days. The transition in O3 and aerosol distributions from tundra to marine conditions was examined several times. The aerosol data clearly show an abrupt change in aerosol scattering properties within the mixed layer from lower values over the tundra to generally higher values over the water. The distinct differences in the heights of the mixed layers in the two regions was also readily apparent. Several cases of enhanced O3 were observed during ABLE-3 in conjunction with enhanced aerosol scattering in layers in the free atmosphere. Examples are presented of the large scale variations of O3 and aerosols observed with the airborne lidar system from near the surface to above the tropopause over the Arctic during ABLE-3

Lidar measurements of ozone and aerosol distributions during the 1992 airborne Arctic stratospheric expedition

The NASA Langley airborne differential absorption lidar system was operated from the NASA Ames DC-8 aircraft during the 1992 Airborne Arctic Stratospheric Expedition to investigate the distribution of stratospheric aerosols and ozone (O3) across the Arctic vortex from January to March 1992. Aerosols from the Mt. Pinatubo eruption were found outside and inside the Arctic vortex with distinctly different scattering characteristics and spatial distributions in the two regions. The aerosol and O3 distributions clearly identified the edge of the vortex and provided additional information on vortex dynamics and transport processes. Few polar stratospheric clouds were observed during the AASE-2; however, those that were found had enhanced scattering and depolarization over the background Pinatubo aerosols. The distribution of aerosols inside the vortex exhibited relatively minor changes during the AASE-2. Ozone depletion inside the vortex as limited to less than or equal to 20 percent in the altitude region from 15-20 km

Large-scale variations in ozone and polar stratospheric clouds measured with airborne lidar during formation of the 1987 ozone hole over Antarctica

A joint field experiment between NASA and NOAA was conducted during August to September 1987 to obtain in situ and remote measurements of key gases and aerosols from aircraft platforms during the formation of the ozone (O3) hole over Antarctica. The ER-2 (advanced U-2) and DC-8 aircraft from the NASA Ames Research Center were used in this field experiment. The NASA Langley Research Center's airborne differential absorption lidar (DIAL) system was operated from the DC-8 to obtain profiles of O3 and polar stratospheric clouds in the lower stratosphere during long-range flights over Antarctica from August 28 to September 29, 1987. The airborne DIAL system was configured to transmit simultaneously four laser wavelengths (301, 311, 622, and 1064 nm) above the DC-8 for DIAL measurements of O3 profiles between 11 to 20 km ASL (geometric altitude above sea level) and multiple wavelength aerosol backscatter measurements between 11 to 24 km ASL. A total of 13 DC-8 flights were made over Antarctica with 2 flights reaching the South Pole. Polar stratospheric clouds (PSC's) were detected in multiple thin layers in the 11 to 21 km ASL altitude range with each layer having a typical thickness of less than 1 km. Two types of PSC's were found based on aerosol backscattering ratios: predominantly water ice clouds (type 2) and clouds with scattering characteristics consistent with binary solid nitric acid/water clouds (type 1). Large-scale cross sections of O3 distributions were obtained. The data provides additional information about a potentially important transport mechanism that may influence the O3 budget inside the vortex. There is also some evidence that strong low pressure systems in the troposphere are associated with regions of lower stratospheric O3. This paper discusses the spatial and temporal variations of O3 inside and outside the polar vortex region during the development of the O3 hole and relates these data to other measurements obtained during this field experiment

Tropospheric ozone and aerosol variability observed at high latitudes with an airborne lidar

Large-scale summertime (July-August) distributions of O3 and aerosols were observed in a broad range of atmosphere conditions over the tundra, ice, and ocean regions near Alaska in 1988 and over the lowlands and boreal forests of Canada in 1990. The tropospheric O3 budget in the high-latitude regions was found to be strongly influenced by stratospheric intrusions, and deposition at the surface was found to be the main sink for O3 in the troposphere. Enhanced levels of O3 were observed in plumes from fires in Alaska and Canada. This paper discusses the large-scale variability of O3 and aerosols observed in the high-latitude regions during these field experiments

Observation of pollution plume capping by a tropopause fold

Airborne lidar measurements reveal a case in which a layer of high-ozone air extruding from a tropopause fold appears to cap a pollution plume and force it to spread out in the lower troposphere. The morphology of the high-ozone layer resembles a three-dimensional model of tropopause fold evolution that produces a low-altitude potential vorticity tube. This is a mechanism that can complete the irreversible transfer of air from the stratosphere, and can also affect pollution levels at the surface if the capping layer reaches the top of the boundary layer.United States. National Aeronautics and Space Administration (Grant NAG1-2306

Restrictive versus liberal red blood cell transfusion strategies for patients with haematological malignancies treated with intensive chemotherapy or radiotherapy, or both, with or without haematopoietic stem cell support

This is the protocol for a review and there is no abstract. The objectives are as follows: To determine the efficacy and safety of restrictive versus liberal transfusion strategies for patients with haematological malignancies treated with intensive chemotherapy or radiotherapy, or both, with or without HSCT

The 2013 Rim Fire: Implications for Predicting Extreme Fire Spread, Pyroconvection, and Smoke Emissions

Abstract The 2013 Rim Fire, which burned over 104,000 ha, was one of the most severe fire events in California's history, in terms of its rapid growth, intensity, overall size, and persistent smoke plume. At least two large pyrocumulonimbus (pyroCb) events were observed, allowing smoke particles to extend through the upper troposphere over a large portion of the Pacific Northwest. However, the most extreme fire spread was observed on days without pyroCb activity or significant regional convection. A diverse archive of ground, airborne, and satellite data collected during the Rim Fire provides a unique opportunity to examine the conditions required for both extreme spread events and pyroCb development. Results highlight the importance of upper-level and nocturnal meteorology, as well as the limitations of traditional fire weather indices. The Rim Fire dataset also allows for a detailed examination of conflicting hypotheses surrounding the primary source of moisture during pyroCb development. All pyroCbs were associated with conditions very similar to those that produce dry thunderstorms. The current suite of automated forecasting applications predict only general trends in fire behavior, and specifically do not predict 1) extreme fire spread events and 2) injection of smoke to high altitudes. While these two exceptions are related, analysis of the Rim Fire shows that they are not predicted by the same set of conditions and variables. The combination of numerical weather prediction data and satellite observations exhibits great potential for improving automated regional-scale forecasts of fire behavior and smoke emissions

Comparison of Aerosol Classification From Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask

Knowledge of aerosol composition and vertical distribution is crucial for assessing the impact of aerosols on climate. In addition, aerosol classification is a key input to CALIOP aerosol retrievals, since CALIOP requires an inference of the lidar ratio in order to estimate the effects of aerosol extinction and backscattering. In contrast, the NASA airborne HSRL-1 directly measures both aerosol extinction and backscatter, and therefore the lidar ratio (extinction-to-backscatter ratio). Four aerosol intensive properties from HSRL-1 are combined to infer aerosol type. Aerosol classification results from HSRL-1 are used here to validate the CALIOP aerosol type inferences

Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols

An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H2O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and greater than 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H2O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H2O absorption-line parameters were performed to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H2O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H2O radiosondes. The H2O distributions measured with the DIAL system differed by less than 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions

Baseline features of the VICTORIA (Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction) trial

Aim Describe the distinguishing features of heart failure (HF) patients with reduced ejection fraction (HFrEF) in the VICTORIA (Vericiguat Global Study in Patients with Heart Failure with Reduced Ejection Fraction) trial. Methods and results Key background characteristics were evaluated in 5050 patients randomized in VICTORIA and categorized into three cohorts reflecting their index worsening HF event. Differences within the VICTORIA population were assessed and compared with PARADIGM-HF (Prospective comparison of ARNI with ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure) and COMMANDER HF (A Study to Assess the Effectiveness and Safety of Rivaroxaban in Reducing the Risk of Death, Myocardial Infarction, or Stroke in Participants with Heart Failure and Coronary Artery Disease Following an Episode of Decompensated Heart Failure). VICTORIA patients had increased risk of mortality and rehospitalization: New York Heart Association class (40% class III), atrial fibrillation (45%), diabetes (47%), hypertension (79%) and mean estimated glomerular filtration rate of 61.5 mL/min/1.73m2. Baseline standard of HF care was very good: 60% received triple therapy. Their N-terminal pro-B-type natriuretic peptide was 3377 pg/mL [interquartile range (IQR) 1992-6380]. Natriuretic peptides were 30% higher level in the 67% patients with HF hospitalization Conclusions VICTORIA comprises a broadly generalizable high-risk population of three unique clinical strata of worsening chronic HFrEF despite very good HF therapy. VICTORIA will establish the role of vericiguat, a soluble guanylate cyclase stimulator, in HFrEF