scholarly journals Vertical profiles and horizontal transport of atmospheric aerosols and trace gases over central Ontario

1998 ◽  
Vol 103 (D17) ◽  
pp. 22015-22037 ◽  
Author(s):  
G. A. Isaac ◽  
C. M. Banic ◽  
W. R. Leaitch ◽  
K. G. Anlauf ◽  
M. D. Couture ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Trace Gases ◽  
Vertical Profiles ◽  
Horizontal Transport

Clear-sky vertical profiles of trace gases as influenced by upstream convective activity

1989 ◽  
Vol 94 (D12) ◽  
pp. 14879-14892 ◽  
Author(s):  
Kenneth E. Pickering ◽  
Russell R. Dickerson ◽  
Winston T. Luke ◽  
Linda J. Nunnermacker
Keyword(s):  
Trace Gases ◽  
Vertical Profiles ◽  
Convective Activity ◽  
Clear Sky

scholarly journals Exploring Atmospheric Aerosols by Twilight Photometry

2008 ◽  
Vol 25 (9) ◽  
pp. 1600-1607 ◽  
Author(s):  
B. Padma Kumari ◽  
S. H. Kulkarni ◽  
D. B. Jadhav ◽  
A. L. Londhe ◽  
H. K. Trimbake
Keyword(s):  
Remote Sensing ◽  
Atmospheric Aerosols ◽  
Integrated Circuit ◽  
Tropical Meteorology ◽  
Indian Institute ◽  
Experimental Setup ◽  
Vertical Profiles ◽  
Remote Sensing Technique ◽  
Passive Remote Sensing ◽  
The Vertical Distribution

Abstract The instrument twilight photometer was designed, developed, and installed at the Indian Institute of Tropical Meteorology (IITM), Pune, India (18°43′N, 73°51′E), to monitor the vertical distribution of atmospheric aerosols. The instrument, based on passive remote sensing technique, is simple and inexpensive. It is operated only during twilights, and the method of retrieval of aerosol profile is based on a simple twilight technique. It functions at a single wavelength (660 nm), and a photomultiplier tube is used as a detector. The amplifier, an important component of the system, was designed and developed by connecting 10 single integrated-circuit (IC) amplifiers in parallel so that the noise at the output is drastically reduced and the sensitivity of the system has been increased. As a result, the vertical profiles are retrieved to a maximum of 120 km. A brief description of the basic principle of twilight technique, the experimental setup, and the method of retrieval of aerosol profiles using the above photometer are detailed in this paper.

scholarly journals Vertical profiles of NO<sub>2</sub>, SO<sub>2</sub>, HONO, HCHO, CHOCHO, and aerosols derived from MAX-DOAS measurements at a rural site in the central-western North China Plain and their relation to emission sources and effects of regional transport

2018 ◽  
Author(s):  
Yang Wang ◽  
Steffen Dörner ◽  
Sebastian Donner ◽  
Sebastian Böhnke ◽  
Isabelle De Smedt ◽  
...  
Keyword(s):  
Trace Gases ◽  
Rural Site ◽  
Optical Absorption Spectroscopy ◽  
Vertical Profiles ◽  
Regional Transport ◽  
Near Surface ◽  
North West ◽  
Mixing Ratios ◽  
Chemistry Research

Abstract. A Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument was deployed in May and June 2016 at a monitoring station (37.18° N, 114.36° E) in the suburban area of Xingtai (one of the most polluted cities in China) during the Atmosphere-Aerosol-Boundary Layer-Cloud (A2BC) and Air chemistry Research In Asia (ARIAs) joint experiments to derive tropospheric vertical profiles of NO2, SO2, HONO, HCHO, CHOCHO and aerosols. Aerosol optical depths derived from MAX-DOAS were found to be consistent with collocated sun-photometer measurements. Also the derived near-surface aerosol extinction and HCHO mixing ratio agree well with coincident visibility meter and in situ HCHO measurements, with mean HCHO near-surface mixing ratios of ~ 3.5 ppb. Underestimates of MAX-DOAS results compared to in situ measurements of NO2 (~ 60 %), SO2 (~ 20 %) are found expectedly due to vertical and horizontal inhomogeneity of trace gases. Vertical profiles of aerosols and NO2, SO2 are reasonably consistent with those measured by a collocated Raman Lidar and aircraft spirals over the station. The deviations can be attributed to differences in sensitivity as a function of altitude and substantial horizontal gradients of pollutants. Aerosols, HCHO, and CHOCHO profiles typically extended to higher altitudes (with 75 % integrated column located below ~ 1.4 km) than did NO2, SO2, and HONO (with 75 % integrated column below ~ 0.5 km) under polluted condition. Lifted layers were systematically observed for all species, (except HONO), indicating accumulation, secondary formation, or long-range transport of the pollutants at higher altitudes. Maximum values routinely occurred in the morning for NO2, SO2, and HONO, but around noon for aerosols, HCHO, and CHOCHO, mainly dominated by photochemistry, characteristic upslope/downslope circulation and PBL dynamics. Significant day-to-day variations are found for all species due to the effect of regional transport and changes in synoptic pattern analysed with HYSPLIT trajectories. Low pollution was often observed for air masses from the north-west (behind cold fronts), and high pollution from the southern areas such as industrialized Wuan. The contribution of regional transport for the pollutants measured at the site during the observation period was estimated to be about 20 % to 30 % for trace gases, and about 50 % for aerosols. In addition, agricultural burning events impacted the day-to-day variations of HCHO, CHOCHO and aerosols.

scholarly journals Estimate of bias in Aura TES HDO/H<sub>2</sub>O profiles from comparison of TES and in situ HDO/H<sub>2</sub>O measurements at the Mauna Loa observatory

2011 ◽  
Vol 11 (9) ◽  
pp. 4491-4503 ◽  
Author(s):  
J. Worden ◽  
D. Noone ◽  
J. Galewsky ◽  
A. Bailey ◽  
K. Bowman ◽  
...  
Keyword(s):  
Bias Correction ◽  
Trace Gases ◽  
Lower Troposphere ◽  
Vertical Profiles ◽  
Thermal Contrast ◽  
Near Surface ◽  
Mauna Loa ◽  
In Situ Data ◽  
Infrared Radiances

Abstract. The Aura satellite Tropospheric Emission Spectrometer (TES) instrument is capable of measuring the HDO/H2O ratio in the lower troposphere using thermal infrared radiances between 1200 and 1350 cm−1. However, direct validation of these measurements is challenging due to a lack of in situ measured vertical profiles of the HDO/H2O ratio that are spatially and temporally co-located with the TES observations. From 11 October through 5 November 2008, we undertook a campaign to measure HDO and H2O at the Mauna Loa observatory in Hawaii for comparison with TES observations. The Mauna Loa observatory is situated at 3.1 km above sea level or approximately 680 hPa, which is approximately the altitude where the TES HDO/H2O observations show the most sensitivity. Another advantage of comparing in situ data from this site to estimates derived from thermal IR radiances is that the volcanic rock is heated by sunlight during the day, thus providing significant thermal contrast between the surface and atmosphere; this thermal contrast increases the sensitivity to near surface estimates of tropospheric trace gases. The objective of this inter-comparison is to better characterize a bias in the TES HDO data, which had been previously estimated to be approximately 5 % too high for a column integrated value between 850 hPa and 500 hPa. We estimate that the TES HDO profiles should be corrected downwards by approximately 4.8 % and 6.3 % for Versions 3 and 4 of the data respectively. These corrections must account for the vertical sensitivity of the TES HDO estimates. We estimate that the precision of this bias correction is approximately 1.9 %. The accuracy is driven by the corrections applied to the in situ HDO and H2O measurements using flask data taken during the inter-comparison campaign and is estimated to be less than 1 %. Future comparisons of TES data to accurate vertical profiles of in situ measurements are needed to refine this bias estimate.

scholarly journals Evidence of horizontal and vertical transport of water in the Southern Hemisphere tropical tropopause layer (TTL) from high-resolution balloon observations

2016 ◽  
Vol 16 (18) ◽  
pp. 12273-12286 ◽  
Author(s):  
Sergey M. Khaykin ◽  
Jean-Pierre Pommereau ◽  
Emmanuel D. Riviere ◽  
Gerhard Held ◽  
Felix Ploeger ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Vapour ◽  
Southern Hemisphere ◽  
Water Budget ◽  
Lower Stratosphere ◽  
Vertical Profiles ◽  
Tropical Tropopause Layer ◽  
Horizontal Transport ◽  
Tropical Tropopause

Abstract. High-resolution in situ balloon measurements of water vapour, aerosol, methane and temperature in the upper tropical tropopause layer (TTL) and lower stratosphere are used to evaluate the processes affecting the stratospheric water budget: horizontal transport (in-mixing) and hydration by cross-tropopause overshooting updrafts. The obtained in situ evidence of these phenomena are analysed using satellite observations by Aura MLS (Microwave Limb Sounder) and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) together with trajectory and transport modelling performed using CLaMS (Chemical Lagrangian Model of the Stratosphere) and HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model. Balloon soundings were conducted during March 2012 in Bauru, Brazil (22.3° S) in the frame of the TRO-Pico campaign for studying the impact of convective overshooting on the stratospheric water budget. The balloon payloads included two stratospheric hygrometers: FLASH-B (Fluorescence Lyman-Alpha Stratospheric Hygrometer for Balloon) and Pico-SDLA instrument as well as COBALD (Compact Optical Backscatter Aerosol Detector) sondes, complemented by Vaisala RS92 radiosondes. Water vapour vertical profiles obtained independently by the two stratospheric hygrometers are in excellent agreement, ensuring credibility of the vertical structures observed. A signature of in-mixing is inferred from a series of vertical profiles, showing coincident enhancements in water vapour (of up to 0.5 ppmv) and aerosol at the 425 K (18.5 km) level. Trajectory analysis unambiguously links these features to intrusions from the Southern Hemisphere extratropical stratosphere, containing more water and aerosol, as demonstrated by MLS and CALIPSO global observations. The in-mixing is successfully reproduced by CLaMS simulations, showing a relatively moist filament extending to 20° S. A signature of local cross-tropopause transport of water is observed in a particular sounding, performed on a convective day and revealing water vapour enhancements of up to 0.6 ppmv as high as the 404 K (17.8 km) level. These are shown to originate from convective overshoots upwind detected by an S-band weather radar operating locally in Bauru. The accurate in situ observations uncover two independent moisture pathways into the tropical lower stratosphere, which are hardly detectable by space-borne sounders. We argue that the moistening by horizontal transport is limited by the weak meridional gradients of water, whereas the fast convective cross-tropopause transport, largely missed by global models, can have a substantial effect, at least at a regional scale.

scholarly journals The CU Airborne MAX-DOAS instrument: vertical profiling of aerosol extinction and trace gases

2013 ◽  
Vol 6 (3) ◽  
pp. 719-739 ◽  
Author(s):  
S. Baidar ◽  
H. Oetjen ◽  
S. Coburn ◽  
B. Dix ◽  
I. Ortega ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Quality ◽  
Spatial Scales ◽  
Trace Gases ◽  
Stray Light ◽  
Aerosol Extinction ◽  
Vertical Profiles ◽  
Maximum Information ◽  
Extinction Coefficients

Abstract. The University of Colorado Airborne Multi-Axis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument uses solar stray light to detect and quantify multiple trace gases, including nitrogen dioxide (NO2), glyoxal (CHOCHO), formaldehyde (HCHO), water vapor (H2O), nitrous acid (HONO), iodine monoxide (IO), bromine monoxide (BrO), and oxygen dimers (O4) at multiple wavelengths (absorption bands at 360, 477, 577, 632 nm) simultaneously in the open atmosphere. The instrument is unique as it (1) features a motion compensation system that decouples the telescope field of view from aircraft movements in real time (<0.35° accuracy), and (2) includes measurements of solar stray light photons from nadir, zenith, and multiple elevation angles forward and below the plane by the same spectrometer/detector system. Sets of solar stray light spectra collected from nadir to zenith scans provide some vertical profile information within 2 km above and below the aircraft altitude, and the vertical column density (VCD) below the aircraft is measured in nadir view. Maximum information about vertical profiles is derived simultaneously for trace gas concentrations and aerosol extinction coefficients over similar spatial scales and with a vertical resolution of typically 250 m during aircraft ascent/descent. The instrument is described, and data from flights over California during the CalNex (California Research at the Nexus of Air Quality and Climate Change) and CARES (Carbonaceous Aerosols and Radiative Effects Study) air quality field campaigns is presented. Horizontal distributions of NO2 VCD (below the aircraft) maps are sampled with typically 1 km resolution, and show good agreement with two ground-based MAX-DOAS instruments (slope = 0.95 ± 0.09, R2 = 0.86). As a case study vertical profiles of NO2, CHOCHO, HCHO, and H2O concentrations and aerosol extinction coefficients, ε, at 477 nm calculated from O4 measurements from a low approach at Brackett airfield inside the South Coast Air Basin (SCAB) are presented. These profiles contain ~12 degrees of freedom (DOF) over a 3.5 km altitude range, an independent information approximately every 250 m. The boundary layer NO2 concentration, and the integral aerosol extinction over height (aerosol optical depth, AOD) agrees well with nearby ground-based in situ NO2 measurement, and AERONET station. The detection limits of NO2, CHOCHO, HCHO, H2O442, &amp;varepsilon;360, &amp;varepsilon;477 for 30 s integration time spectra recorded forward of the plane are 5 ppt, 3 ppt, 100 ppt, 42 ppm, 0.004 km−1, 0.002 km−1 in the free troposphere (FT), and 30 ppt, 16 ppt, 540 ppt, 252 ppm, 0.012 km−1, 0.006 km−1 inside the boundary layer (BL), respectively. Mobile column observations of trace gases and aerosols are complimentary to in situ observations, and help bridge the spatial scales that are probed by satellites and ground-based observations, and predicted by atmospheric models.

scholarly journals Atmospheric Aerosols and Trace Gases

2020 ◽  
pp. 93-116
Author(s):  
Suvarna Fadnavis ◽  
Anoop Sharad Mahajan ◽  
Ayantika Dey Choudhury ◽  
Chaitri Roy ◽  
Manmeet Singh ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Trace Gases

scholarly journals Simulation of trace gases and aerosols over the Indian domain: evaluation of the WRF-Chem Model

2013 ◽  
Vol 13 (5) ◽  
pp. 12287-12336 ◽  
Author(s):  
M. Michael ◽  
A. Yadav ◽  
S. N. Tripathi ◽  
V. P. Kanawade ◽  
A. Gaur ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Black Carbon ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Indian Subcontinent ◽  
Trace Gases ◽  
Atmospheric Composition ◽  
Emission Rates ◽  
Vertical Profiles ◽  
Monsoon Period

Abstract. The "online" meteorological and chemical transport Weather Research and Forecasting/Chemistry (WRF-Chem) model has been implemented over the Indian subcontinent for three consecutive summers in 2008, 2009 and 2010 to study the aerosol properties over the domain. The initial and boundary conditions are obtained from NCAR reanalysis data. The emission rates of sulfur dioxide, black carbon, organic carbon and PM2.5, which are developed over India at a grid resolution of 0.25° × 0.25° have been used in the present study. The remaining emissions are obtained from global inventories (RETRO and EDGAR). The model simulated the meteorological parameters, trace gases and particulate matter. Predicted mixing ratios of trace gases (Ozone, carbon monoxide and sulfur dioxide) are compared with ground based observations over Kanpur. Simulated aerosol optical depth are compared with those observed at nine Aerosol Robotic Network stations (AERONET). The simulations show that the aerosol optical depth of the less polluted regions is better simulated compared to that of the locations where the aerosol loading is very high. The vertical profiles of extinction coefficient observed at Kanpur Micropulse Lidar Network (MPLNET) station is in agreement with the simulated values for altitudes greater than 1.5 km and qualitatively simulate the elevated layers of aerosols. The simulated mass concentration of black carbon shows very good correlation with observations, due to the better local emission inventory used. The vertical profiles of black carbon at various locations have also been compared with observations from aircraft campaign held during pre-monsoon period of 2008 and 2009 resulting in good agreement. This study shows that WRF-Chem model captures many important features of the observations and therefore can be used for understanding and predicting regional atmospheric composition over Indian subcontinent.

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