Quality-based generation of weather radar Cartesian products
Summary: Weather radar data are processed to obtain various 2D products. In this research, an algorithm of interpolation of polar reflectivity data with respect to quality index (QI) data is applied to find the Cartesian reflectivity as PPI products and generate a corresponding QI field. On this basis, quality-based algorithms for the generation of the standard products have been developed: ETOP, MAX, and VIL. Moreover a detection of convection has been defined as a specific combination of the products.
Atmos. Meas. Tech., 8, 2173-2181, doi:10.5194/amt-8-2173-2015, 2015
Scanning supersaturation condensation particle counter applied as a nano-CCN counter for size-resolved analysis of the hygroscopicity and chemical composition of nanoparticles
Atmos. Meas. Tech., 8, 2161-2172, doi:10.5194/amt-8-2161-2015, 2015
A theoretical study of the effect of subsurface oceanic bubbles on the enhanced aerosol optical depth band over the southern oceans as detected from MODIS and MISR
Summary: Submerged oceanic bubbles, which could have a much longer life span than whitecaps or bubble rafts, have been hypothesized to increase the water-leaving radiance and thus affect satellite-based estimates of water-leaving radiance to non-trivial levels. This study explores this effect further to determine if such bubbles are of sufficient magnitude to impact satellite aerosol optical depth retrievals through perturbation of the lower boundary conditions.
Atmos. Meas. Tech., 8, 2149-2160, doi:10.5194/amt-8-2149-2015, 2015
Aircraft measurements of BrO, IO, glyoxal, NO2, H2O, O2–O2 and aerosol extinction profiles in the tropics: comparison with aircraft-/ship-based in situ and lidar measurements
Summary: Tropospheric halogens and small oxygenated VOC (OVOC) modify tropospheric HOx and NOx, O3 and aerosols. We have measured bromine monoxide (BrO), iodine monoxide (IO), glyoxal (CHOCHO) profiles from research aircraft in the tropical troposphere and compare with ship- and aircraft-based in situ sensors. Our measurements point to the need to improve the representation of halogens and organic carbon sources in atmospheric models.
Atmos. Meas. Tech., 8, 2121-2148, doi:10.5194/amt-8-2121-2015, 2015
Round-robin evaluation of nadir ozone profile retrievals: methodology and application to MetOp-A GOME-2
Summary: This work thoroughly discusses a methodology, as summarized in a flowchart, for the round-robin evaluation and geophysical validation of nadir ozone profile retrievals and applies the proposed best practice to a pair of optimal-estimation algorithms run on exactly the same level-1 radiance measurements. The quality assessment combines data set content studies, information content studies, and comparisons with ground-based reference measurements.
Atmos. Meas. Tech., 8, 2093-2120, doi:10.5194/amt-8-2093-2015, 2015
Big grains go far: understanding the discrepancy between tephrochronology and satellite infrared measurements of volcanic ash
Summary: We attempt to understand why volcanic ash grains found 100s of km from their source volcanoes (cryptotephra), which are typically 20–125 microns in length, are much larger than the size distributions measured by satellite remote sensing, which are centred at less than 10 microns. Our observations and models show that cryptotephra-sized grains are to be expected in distal plumes. Retrievals of effective radius made on simulated satellite images are shown to be biased toward smaller values.
Atmos. Meas. Tech., 8, 2069-2091, doi:10.5194/amt-8-2069-2015, 2015
Robust, spatially scanning, open-path TDLAS hygrometer using retro-reflective foils for fast tomographic 2-D water vapor concentration field measurements
Summary: We have developed a fast, spatially direct scanning tunable diode laser absorption spectrometer (dTDLAS) that combines four polygon-mirror based scanning units with low-cost retro-reflective foils. The spectrometer is a robust and easy to set up instrument for tomographic reconstructions of 2-D-concentration fields that can be considered as a good basis for future field measurements in environmental research.
Atmos. Meas. Tech., 8, 2061-2068, doi:10.5194/amt-8-2061-2015, 2015
Methodology for determining multilayered temperature inversions
Summary: Temperature inversion layers originate based on the combined forcing of local- and large-scale synoptic meteorology. A numerical procedure based on a linear interpolation function of variable length that minimizes an error function set a priori is proposed to extract thermodynamic information of the multilayered thermal structure. The method is demonstrated to detect surface-based inversion and multilayered elevated inversions present often in high-latitude atmospheres.
Atmos. Meas. Tech., 8, 2051-2060, doi:10.5194/amt-8-2051-2015, 2015
Airborne in situ vertical profiling of HDO / H216O in the subtropical troposphere during the MUSICA remote sensing validation campaign
Atmos. Meas. Tech., 8, 2037-2049, doi:10.5194/amt-8-2037-2015, 2015
Measurements of methane emissions from natural gas gathering facilities and processing plants: measurement methods
Summary: This report presents an overview and detailed description of the measurement methods, analysis approach, and example data from a 10-week EDF-sponsored field campaign measuring methane emissions from natural gas gathering and processing facilities across the US. The dual-tracer ratio method was employed to quantify methane release rates and identify emission sources at a wide variety of facilities, using downwind measurements of CH4, C2H6, CO2, and CO with N2O and C2H2 as tracers.
Atmos. Meas. Tech., 8, 2017-2035, doi:10.5194/amt-8-2017-2015, 2015
Comparing satellite- to ground-based automated and manual cloud coverage observations – a case study
Atmos. Meas. Tech., 8, 2001-2015, doi:10.5194/amt-8-2001-2015, 2015
Tomographic retrieval of water vapour and temperature around polar mesospheric clouds using Odin-SMR
Summary: Polar mesospheric clouds are clouds that form in the summer polar mesopause, 80km above the surface. In this study we present new measurements by the Odin satellite, which are able to determine water vapour, temperature and cloud coverage with a high resolution and a large geographical coverage. Using these data we can see structures in the clouds and background atmosphere that have not been detectable by previous measurements.
Atmos. Meas. Tech., 8, 1981-1999, doi:10.5194/amt-8-1981-2015, 2015
The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation
Summary: We present a new real-time algorithm for compensation of the filter-loading effect in filter photometers, based on a two parallel spot measurement of optical absorption. This algorithm has been incorporated into the new Aethalometer AE33. Intercomparison studies show excellent reproducibility of the AE33 measurements and very good agreement with post-processed data obtained using earlier aethalometer models and other filter-based absorption photometers.
Atmos. Meas. Tech., 8, 1965-1979, doi:10.5194/amt-8-1965-2015, 2015
Using self-organising maps to explore ozone profile validation results – SCIAMACHY limb compared to ground-based lidar observations
Atmos. Meas. Tech., 8, 1951-1963, doi:10.5194/amt-8-1951-2015, 2015
A model sensitivity study of the impact of clouds on satellite detection and retrieval of volcanic ash
Summary: Water and ice clouds affect detection and retrieval of volcanic ash clouds by satellite instruments. Synthetic infrared satellite images were generated for the Eyjafjallajokull 2010 and Grimsvotn 2011 eruptions by combining weather forecast, ash transport and radiative transfer modelling. Clouds decreased the number of pixels identified as ash and generally increased the retrieved ash-mass loading compared to the cloudless case; however, large differences were seen between scenes.
Atmos. Meas. Tech., 8, 1935-1949, doi:10.5194/amt-8-1935-2015, 2015
On the microwave optical properties of randomly oriented ice hydrometeors
Summary: The optical properties of randomly oriented ice hydrometeors are reviewed from a perspective of microwave mass retrievals. The soft particle approximation is found to be highly problematic, and the alternative approach presented by Geer and Baordo (2014) should instead be used. We present a simplified version of this approach, and point out several critical limitations of existing DDA data.
Atmos. Meas. Tech., 8, 1913-1933, doi:10.5194/amt-8-1913-2015, 2015
Observing crosswind over urban terrain using scintillometer and Doppler lidar
Atmos. Meas. Tech., 8, 1901-1911, doi:10.5194/amt-8-1901-2015, 2015
The Radio Occultation Processing Package, ROPP
Summary: This paper describes the Radio Occultation Processing Package, ROPP, which is a suite of freely available programs provided by EUMETSAT for the processing of radio occultation data. Its capabilities are briefly reviewed, and examples of its use are given. Some current and prospective uses of ROPP are listed.
Atmos. Meas. Tech., 8, 1887-1899, doi:10.5194/amt-8-1887-2015, 2015
Low-level mixing height detection in coastal locations with a scanning Doppler lidar
Atmos. Meas. Tech., 8, 1875-1885, doi:10.5194/amt-8-1875-2015, 2015
Zeeman effect in atmospheric O2 measured by ground-based microwave radiometry
Summary: In this work we study the Zeeman effect on stratospheric O2 using ground-based microwave radiometer measurements. The interaction of the Earth magnetic field with the oxygen dipole leads to a splitting of O2 energy states which polarizes the emission spectra. A special campaign was carried out in order to measure for the first time the polarization state of the radiation due to the Zeeman effect in the main isotopologue of oxygen from ground-based microwave measurements.
Atmos. Meas. Tech., 8, 1863-1874, doi:10.5194/amt-8-1863-2015, 2015