scholarly journals Retrieval of NO2 Column Amounts from Ground-Based Hyperspectral Imaging Sensor Measurements

2019 ◽  
Vol 11 (24) ◽  
pp. 3005 ◽  
Author(s):  
Hyeon-Ju Park ◽  
Jin-Soo Park ◽  
Sang-Woo Kim ◽  
Heesung Chong ◽  
Hana Lee ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Zenith Angle ◽  
Vertical Profile ◽  
Azimuth Angle ◽  
Fitting Method ◽  
Intensive Observation ◽  
Imaging Sensor ◽  
Total Column ◽  
Observation Period ◽  
Good Agreement

Total column amounts of NO2 (TCN) were estimated from ground-based hyperspectral imaging sensor (HIS) measurements in a polluted urban area (Seoul, Korea) by applying the radiance ratio fitting method with five wavelength pairs from 400 to 460 nm. We quantified the uncertainty of the retrieved TCN based on several factors. The estimated TCN uncertainty was up to 0.09 Dobson unit (DU), equivalent to 2.687 × 1020 molecules m−2) given a 1° error for the observation geometries, including the solar zenith angle, viewing zenith angle, and relative azimuth angle. About 0.1 DU (6.8%) was estimated for an aerosol optical depth (AOD) uncertainty of 0.01. In addition, the uncertainty due to the NO2 vertical profile was 14% to 22%. Compared with the co-located Pandora spectrophotometer measurements, the HIS captured the temporal variation of the TCN during the intensive observation period. The correlation between the TCN from the HIS and Pandora also showed good agreement, with a slight positive bias (bias: 0.6 DU, root mean square error: 0.7 DU).

scholarly journals PERBANDINGAN PROFIL HUJAN VERTIKAL RADAR CUACA DENGAN MICRO RAIN RADAR SELAMA KEJADIAN HUJAN SEDANG (Studi Kasus : Intensive Observation Period 2016)

2016 ◽  
Vol 17 (2) ◽  
pp. 57
Author(s):  
Sunu Tikno ◽  
Rino Bahtiar Yahya ◽  
Sara Aisyah Syafira
Keyword(s):  
Vertical Profile ◽  
Rain Rate ◽  
Weather Radar ◽  
Instrument Making ◽  
Rainfall Events ◽  
Processing Data ◽  
Significant Attenuation ◽  
Intensive Observation ◽  
Rain Radar ◽  
Observation Period

IntisariMicro Rain Radar (MRR) merupakan suatu instrumen pengamatan hujan, yang beroperasi secara vertikal. Sementara itu, radar cuaca WR-2100 biasa digunakan untuk membuat suatu profil yang berupa cakupan area.  Akan tetapi, dengan pengolahan lebih lanjut, data suatu radar cuaca seperti radar cuaca WR-2100 tersebut juga dapat digunakan untuk menampilkan profil vertikal salah satu parameternya di suatu lokasi tertentu. Penelitian kali ini membandingkan profil vertikal hujan di Dramaga, Bogor berdasarkan nilai rain rate nya yang diperoleh dari MRR yang beroperasi secara langsung di lokasi tersebut dengan profil serupa yang diperoleh dari radar cuaca WR-2100 yang beroperasi di lokasi berbeda, yaitu di Serpong, Tangerang Selatan. Hasil penelitian menunjukan bahwa kedua instrumen tersebut mendeteksi adanya nilai rain rate pada waktu-waktu yang bersamaan, namun dengan nilai yang lebih tinggi oleh radar cuaca WR-2100 untuk lapisan-lapisan yang lebih tinggi, yang terutama diduga karena atenuasi yang lebih besar dan signifikan yang terjadi pada proses pengukuran oleh MRR untuk lapisan-lapisan yang lebih tinggi pada saat kejadian-kejadian hujan sedang.  AbstractMicro Rain Radar (MRR) is an instrument to observe precipitation, especially rainfall, that operate vertically. Besides, a weather radar, WR-2100, is an instrument making profile in an area scope. By doing further processing, data of weather radar WR-2100 can be used to show vertical profile of a certain parameter in a certain location. This study compared vertical profile of rain rate at Dramaga, Bogor, based on data of MRR operated in same location with that based on data of weather radar WR-2100 operated in different location, which is Serpong, Tangerang Selatan. Results of the study showed that both instruments detected rain rate values on same times, while the values are higher at higher altitudes for weather radar WR-2100 than for MRR due to higher and more significant attenuation happened in MRR operation at higher altitude in moderate rainfall events. 

Numerical Studies of Cyclogenesis Events during the Second Intensive Observation Period (IOP-2) of GALE

1990 ◽  
Vol 118 (2) ◽  
pp. 218-233 ◽  
Author(s):  
Chi-Sann Liou ◽  
Carlyle H. Wash ◽  
Stacey M. Heikkinen ◽  
Russell L. Elsberry
Keyword(s):  
Numerical Studies ◽  
Intensive Observation ◽  
Observation Period

scholarly journals Precipitation at Dumont d'Urville, Adélie Land, East Antarctica: the APRES3 field campaigns dataset

2018 ◽  
Vol 10 (3) ◽  
pp. 1605-1612 ◽  
Author(s):  
Christophe Genthon ◽  
Alexis Berne ◽  
Jacopo Grazioli ◽  
Claudio Durán Alarcón ◽  
Christophe Praz ◽  
...  
Keyword(s):  
Climate Models ◽  
Data Repository ◽  
X Band ◽  
Intensive Observation ◽  
Radar Measurements ◽  
Scientific Results ◽  
Antarctic Precipitation ◽  
Severe Shortage ◽  
Observation Period

Abstract. Compared to the other continents and lands, Antarctica suffers from a severe shortage of in situ observations of precipitation. APRES3 (Antarctic Precipitation, Remote Sensing from Surface and Space) is a program dedicated to improving the observation of Antarctic precipitation, both from the surface and from space, to assess climatologies and evaluate and ameliorate meteorological and climate models. A field measurement campaign was deployed at Dumont d'Urville station at the coast of Adélie Land in Antarctica, with an intensive observation period from November 2015 to February 2016 using X-band and K-band radars, a snow gauge, snowflake cameras and a disdrometer, followed by continuous radar monitoring through 2016 and beyond. Among other results, the observations show that a significant fraction of precipitation sublimates in a dry surface katabatic layer before it reaches and accumulates at the surface, a result derived from profiling radar measurements. While the bulk of the data analyses and scientific results are published in specialized journals, this paper provides a compact description of the dataset now archived in the PANGAEA data repository (https://www.pangaea.de, https://doi.org/10.1594/PANGAEA.883562) and made open to the scientific community to further its exploitation for Antarctic meteorology and climate research purposes.

scholarly journals Retrieval of stratospheric and tropospheric BrO columns from multi-axis DOAS measurements at Reunion Island (21° S, 56° E)

2007 ◽  
Vol 7 (3) ◽  
pp. 8261-8308 ◽  
Author(s):  
N. Theys ◽  
M. Van Roozendael ◽  
F. Hendrick ◽  
C. Fayt ◽  
C. Hermans ◽  
...  
Keyword(s):  
Measurement Data ◽  
Retrieval Algorithm ◽  
Reunion Island ◽  
Spectral Measurements ◽  
Réunion Island ◽  
One Year ◽  
Chemical Fields ◽  
Latitudinal Band ◽  
Observation Period ◽  
Good Agreement

Abstract. Spectral measurements of BrO using zenith-sky and off-axis viewing geometries are combined in a linear multiple regression retrieval algorithm to provide stratospheric and tropospheric BrO vertical columns. One year of measurement data are investigated over Reunion-Island (20.9° S, 55.5° E), from July 2004 to July 2005. No seasonal variations of the retrieved BrO columns could be observed, in line with previous studies. A comparison between the stratospheric columns retrieved at 45°, 80°, 85°, 87.5° and 92.5° solar zenith angles and photochemical simulations initialized by chemical fields from the 3-D-CTM SLIMCAT and further constrained by observed NO2 profiles shows a good agreement only by considering a contribution from the very short-lived organic bromine substances to the stratospheric inorganic bromine budget, of 6 to 8 pptv. Furthermore, stratospheric BrO profiles retrieved from late twilight zenith-sky observations are consistent with a total inorganic bromine (Bry) loading of approximately 23 pptv. This represents 6 to 7 pptv more than can be supplied by long-lived organic bromine sources, and therefore supports an added contribution from very short-lived organic bromine substances as recently suggested in several other studies. Moreover strong evidences are presented for the existence of a substantial amount of BrO in the tropical free-troposphere, around 6 km altitude, possibly supplied by the decomposition of short-lived biogenic bromine organic compounds. Tropospheric BrO vertical columns of 1.1±0.45×1013 molec/cm2 are derived for the entire observation period. Comparisons between ground-based BrO vertical columns and total BrO columns derived from SCIAMACHY (onboard the ENVISAT satellite) nadir observations in a latitudinal band centered around 21° S present a good level of consistency, which further strengthens the conclusions of our study.

scholarly journals The Unconventional Eyewall Replacement Cycle of Hurricane Ophelia (2005)

2021 ◽  
Author(s):  
Muhammad Naufal Razin ◽  
Michael M. Bell
Keyword(s):  
Intensity Change ◽  
Wind Maximum ◽  
Low Level ◽  
Tangential Wind ◽  
Eyewall Replacement Cycle ◽  
Flight Level ◽  
Intensive Observation ◽  
Observation Period ◽  
Replacement Cycle

AbstractHurricane Ophelia (2005) underwent an unconventional eyewall replacement cycle (ERC) as it was a Category 1 storm located over cold sea surface temperatures near 23°C. The ERC was analyzed using airborne radar, flight-level, and dropsonde data collected during the Hurricane Rainband and Intensity Change Experiment (RAINEX) intensive observation period on 11 September 2005. Results showed that the spin-up of the secondary tangential wind maximum during the ERC can be attributed to the efficient convergence of absolute angular momentum by the mid-level inflow of Ophelia’s dominantly stratiform rainbands. This secondary tangential wind maximum strongly contributed to the azimuthal mean tangential wind field, which is conducive for increased low-level supergradient winds and corresponding outflow. The low-level supergradient forcing enhanced convergence to form a secondary eyewall. Ophelia provides a unique example of an ERC occurring in a weaker storm with predominantly stratiform rainbands, suggesting an important role of stratiform precipitation processes in the development of secondary eyewalls.

The variability of evaporation during the HAPEX-Sahel Intensive Observation Period

1997 ◽  
Vol 188-189 ◽  
pp. 385-399 ◽  
Author(s):  
J.H.C. Gash ◽  
P. Kabat ◽  
B.A. Monteny ◽  
M. Amadou ◽  
P. Bessemoulin ◽  
...  
Keyword(s):  
Intensive Observation ◽  
Observation Period

scholarly journals Estimation of Antarctic ozone loss from ground-based total column measurements

2010 ◽  
Vol 10 (14) ◽  
pp. 6569-6581 ◽  
Author(s):  
J. Kuttippurath ◽  
F. Goutail ◽  
J.-P. Pommereau ◽  
F. Lefèvre ◽  
H. K. Roscoe ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Sensitivity Study ◽  
Satellite Measurements ◽  
Macquarie Island ◽  
Ozone Loss ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Ozone Column ◽  
Total Column ◽  
Good Agreement

Abstract. The passive tracer method is used to estimate ozone loss from ground-based measurements in the Antarctic. A sensitivity study shows that the ozone depletion can be estimated within an accuracy of ~4%. The method is then applied to the ground-based observations from Arrival Heights, Belgrano, Concordia, Dumont d'Urville, Faraday, Halley, Marambio, Neumayer, Rothera, South Pole, Syowa, and Zhongshan for the diagnosis of ozone loss in the Antarctic. On average, the ten-day boxcar average of the vortex mean ozone column loss deduced from the ground-based stations was about 55±5% in 2005–2009. The ozone loss computed from the ground-based measurements is in very good agreement with those derived from satellite measurements (OMI and SCIAMACHY) and model simulations (REPROBUS and SLIMCAT), where the differences are within ±3–5%. The historical ground-based total ozone observations in October show that the depletion started in the late 1970s, reached a maximum in the early 1990s and stabilised afterwards due to saturation. There is no indication of ozone recovery yet. At southern mid-latitudes, a reduction of 20–50% is observed for a few days in October–November at the newly installed Rio Gallegos station. Similar depletion of ozone is also observed episodically during the vortex overpasses at Kerguelen in October–November and at Macquarie Island in July–August of the recent winters. This illustrates the significance of measurements at the edges of Antarctica.

scholarly journals Probing the Fog Life Cycles in the Namib Desert

2019 ◽  
Vol 100 (12) ◽  
pp. 2491-2507 ◽  
Author(s):  
Robert Spirig ◽  
Roland Vogt ◽  
Jarl Are Larsen ◽  
Christian Feigenwinter ◽  
Andreas Wicki ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Life Cycles ◽  
Cloud Base ◽  
Spatial And Temporal Patterns ◽  
Liquid Water Path ◽  
Field Campaign ◽  
First Results ◽  
Fog Deposition ◽  
Intensive Observation ◽  
Observation Period

Abstract An intensive observation period was conducted in September 2017 in the central Namib, Namibia, as part of the project Namib Fog Life Cycle Analysis (NaFoLiCA). The purpose of the field campaign was to investigate the spatial and temporal patterns of the coastal fog that occurs regularly during nighttime and morning hours. The fog is often linked to advection of a marine stratus that intercepts with the terrain up to 100 km inland. Meteorological data, including cloud base height, fog deposition, liquid water path, and vertical profiles of wind speed/direction and temperature, were measured continuously during the campaign. Additionally, profiles of temperature and relative humidity were sampled during five selected nights with stratus/fog at both coastal and inland sites using tethered balloon soundings, drone profiling, and radiosondes. This paper presents an overview of the scientific goals of the field campaign; describes the experimental setup, the measurements carried out, and the meteorological conditions during the intensive observation period; and presents first results with a focus on a single fog event.

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