scholarly journals CARIBIC DOAS observations of nitrous acid and formaldehyde in a large convective cloud

2014 ◽  
Vol 14 (13) ◽  
pp. 6621-6642 ◽  
Author(s):  
K.-P. Heue ◽  
H. Riede ◽  
D. Walter ◽  
C. A. M. Brenninkmeijer ◽  
T. Wagner ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
World Wide ◽  
Convective Cloud ◽  
Global Scale ◽  
Box Model ◽  
Convective System ◽  
Mixing Ratios ◽  
The World ◽  
Tropopause Region

Abstract. The chemistry in large thunderstorm clouds is influenced by local lightning-NOx production and uplift of boundary layer air. Under these circumstances trace gases like nitrous acid (HONO) or formaldehyde (HCHO) are expected to be formed or to reach the tropopause region. However, up to now only few observations of HONO at this altitude have been reported. Here we report on a case study where enhancements in HONO, HCHO and nitrogen oxides (NOx) were observed by the CARIBIC flying laboratory (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container). The event took place in a convective system over the Caribbean Sea in August 2011. Inside the cloud the light path reaches up to 100 km. Therefore the DOAS instrument on CARIBIC was very sensitive to the tracers inside the cloud. Based on the enhanced slant column densities of HONO, HCHO and NO2, average mixing ratios of 37, 468 and 210 ppt, respectively, were calculated. These data represent averages for constant mixing ratios inside the cloud. However, a large dependency on the assumed profile is found; for HONO a mixing ratio of 160 ppt is retrieved if the total amount is assumed to be situated in the uppermost 2 km of the cloud. The NO in situ instrument measured peaks up to 5 ppb NO inside the cloud; the background in the cloud was about 1.3 ppb, and hence clearly above the average outside the cloud (≈ 150 ppt). The high variability and the fact that the enhancements were observed over a pristine marine area led to the conclusion that, in all likelihood, the high NO concentrations were caused by lighting. This assumption is supported by the number of flashes that the World Wide Lightning Location Network (WWLLN) counted in this area before and during the overpass. The chemical box model CAABA is used to estimate the NO and HCHO source strengths which are necessary to explain our measurements. For NO a source strength of 10 × 109 molec cm−2 s−1 km−1 is found, which corresponds to the lightning activity as observed by the World Wide Lightning Location network, and lightning emissions of 5 × 1025 NO molec flash−1 (2.3–6.4 × 1025). The uncertainties are determined by a change of the input parameters in the box model, the cloud top height and the flash density. The emission rate per flash is scaled up to a global scale and 1.9 (1.4–2.5) tg N a−1 is estimated. The HCHO updraught is of the order of 120 × 109 molec cm−2 s−1 km−1. Also isoprene and CH3OOH as possible HCHO sources are discussed.

scholarly journals CARIBIC DOAS observations of nitrous acid and formaldehyde in a large convective cloud

2013 ◽  
Vol 13 (9) ◽  
pp. 24343-24403
Author(s):  
K.-P. Heue ◽  
H. Riede ◽  
D. Walter ◽  
C. A. M. Brenninkmeijer ◽  
T. Wagner ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Detection Limit ◽  
Nitrous Acid ◽  
World Wide ◽  
Marine Boundary Layer ◽  
Convective Cloud ◽  
Observation System ◽  
Oh Radicals ◽  
Actual System ◽  
The World

Abstract. The CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) flying laboratory measures once per month the chemical composition at cruise altitude (10...12 km) during 4 consecutive Lufthansa flights. Here we present a case study of enhanced nitrogen oxides (NOx), nitrous acid (HONO), and formaldehyde (HCHO) in a thunderstorm cloud over the Caribbean islands of Guadeloupe in August 2011. Nitrous acid is an important reservoir gas for OH radicals, and only few observations of HONO at cruise altitude exist. CARIBIC is designed as a long period atmospheric observation system, the actual system has been flying almost monthly since 8 yr now. During this period only very few similar events (one since 2008) were observed. Due to multiple scattering the light path inside clouds is enhanced, thereby lowering the detection limit of the DOAS instrument. Under background conditions the detection limits are 46 ppt for HONO, 387 ppt for \\chem{HCHO}, and 100 ppt for NO2 and are roughly three times lower inside the cloud. Based on radiative transfer simulations we estimate the path length to 90{\\ldots}100 km and the cloud top height to ≈15 km. The inferred mixing ratios of HONO, HCHO and NO2 are 37 ppt, 400 ppt and 170 ppt, respectively. Bromine monoxide (BrO) remained below the detection limit of 1 ppt. Because the uplifted air masses originated from the remote marine boundary layer and lightning was observed in the area by the World Wide Lightning Location Network several hours prior to the measurement, the NO (≈1.5 ppb) enhancement was in all likelihood caused by lightning. The main source for the observed HCHO is probably updraught from the boundary layer, because the chemical formation of formaldehyde due to methane oxidation is too weak. Besides HCHO also CH3OOH and isoprene are considered as precursors. The chemical box model CAABA is used to estimate the \\chem{NO} and HCHO source strengths, which are necessary to explain our measurements. For NO a source strength of 8.25 × 109 molec cm−2 s−1 km−1 is found, which corresponds to the lightning activity as observed by the World Wide Lightning Location network and a lightning emission of 4.2 × 1025 NO molec/flash. The HCHO updraught is of the order of 121 × 109 molec cm−2 s−1 km−1. Also isoprene and CH3OOH as possible HCHO sources were studied and similar source strengths were found.

scholarly journals Exploring the atmospheric chemistry of nitrous acid (HONO) at a rural site in Southern China

2012 ◽  
Vol 12 (3) ◽  
pp. 1497-1513 ◽  
Author(s):  
X. Li ◽  
T. Brauers ◽  
R. Häseler ◽  
B. Bohn ◽  
H. Fuchs ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Southern China ◽  
Rural Site ◽  
Pearl River Delta Region ◽  
Additional Source ◽  
Mixing Ratios ◽  
Photolysis Frequency ◽  
The Pearl River

Abstract. We performed measurements of nitrous acid (HONO) during the PRIDE-PRD2006 campaign in the Pearl River Delta region 60 km north of Guangzhou, China, for 4 weeks in June 2006. HONO was measured by a LOPAP in-situ instrument which was setup in one of the campaign supersites along with a variety of instruments measuring hydroxyl radicals, trace gases, aerosols, and meteorological parameters. Maximum diurnal HONO mixing ratios of 1–5 ppb were observed during the nights. We found that the nighttime build-up of HONO can be attributed to the heterogeneous NO2 to HONO conversion on ground surfaces and the OH + NO reaction. In addition to elevated nighttime mixing ratios, measured noontime values of ≈200 ppt indicate the existence of a daytime source higher than the OH + NO→HONO reaction. Using the simultaneously recorded OH, NO, and HONO photolysis frequency, a daytime additional source strength of HONO (PM) was calculated to be 0.77 ppb h−1 on average. This value compares well to previous measurements in other environments. Our analysis of PM provides evidence that the photolysis of HNO3 adsorbed on ground surfaces contributes to the HONO formation.

Developing Trust for Electronic Commerce

2011 ◽  
pp. 39-80 ◽  
Author(s):  
Dieter Fink
Keyword(s):  
Electronic Commerce ◽  
World Wide ◽  
Global Scale ◽  
Body Language ◽  
Internet Technology ◽  
The Internet ◽  
The Past ◽  
New Information ◽  
The World ◽  
The Web

While much attention is currently being devoted to solving technological challenges of the Internet, for example increasing the bandwidth on existing narrowband network platforms to overcome bottlenecks, little attention appears to be given to the nontechnical aspects. This has been a mistake in the past as human resistance to, or incompetence during, the introduction of new Information Technology (IT) often caused Information Systems (IS) to fail. By focusing on a broad range of technical and nontechnical elements early in the adoption of Internet technology, we have the opportunity to avoid the mistakes made in the past. The Internet has given rise to electronic commerce (e-commerce) through the use of the World Wide Web (Web). E-commerce, by its nature, offers enormous possibilities but in an uncontrolled environment. Therefore, for e-commerce to be accepted, trust must be established as soon as interaction with a Web site begins. In the virtual environment of the Web trust has become even more important because the parties are not in physical proximity. There are no handshakes or body language to be observed when closing a deal. Furthermore, jurisdiction is unclear. Developments on a global scale are required that provide assurance that e-commerce can be conducted in a ‘trusting’ manner.

scholarly journals Global Deliberative Democracy and Climate Change: Insights from World Wide Views on Global Warming in Australia

2011 ◽  
Vol 8 (3) ◽  
Author(s):  
Chris Riedy ◽  
Jade Herriman
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
World Wide ◽  
Global Climate ◽  
Climate Change Policy ◽  
Global Scale ◽  
Climate Change Response ◽  
Deliberative System ◽  
The World ◽  
Change Response

On 26 September 2009, approximately 4,000 citizens in 38 countries participated in World Wide Views on Global Warming (WWViews). WWViews was an ambitious first attempt to convene a deliberative mini-public at a global scale, giving people from around the world an opportunity to deliberate on international climate policy and to make recommendations to the decision-makers meeting at the United Nations Climate Change Conference in Copenhagen (COP-15) in December 2009. In this paper, we examine the role that deliberative mini-publics can play in facilitating the emergence of a global deliberative system for climate change response. We pursue this intent through a reflective evaluation of the Australian component of the World Wide Views on Global Warming project (WWViews). Our evaluation of WWViews is mixed. The Australian event was delivered with integrity and feedback from Australian participants was almost universally positive. Globally, WWViews demonstrated that it is feasible to convene a global mini-public to deliberate on issues of global relevance, such as climate change. On the other hand, the contribution of WWViews towards the emergence of a global deliberative system for climate change response was limited and it achieved little influence on global climate change policy. We identify lessons for future global mini-publics, including the need to prioritise the quality of deliberation and provide flexibility to respond to cultural and political contexts in different parts of the world. Future global mini-publics may be more influential if they seek to represent discourse diversity in addition to demographic profiles, use designs that maximise the potential for transmission from public to empowered space, run over longer time periods to build momentum for change and experiment with ways of bringing global citizens together in a single process instead of discrete national events.

scholarly journals Upper tropospheric water vapour and its interaction with cirrus clouds as seen from IAGOS long-term routine in situ observations

2017 ◽  
Vol 200 ◽  
pp. 229-249 ◽  
Author(s):  
Andreas Petzold ◽  
Martina Krämer ◽  
Patrick Neis ◽  
Christian Rolf ◽  
Susanne Rohs ◽  
...  
Keyword(s):  
Water Vapour ◽  
Dynamic Equilibrium ◽  
North Atlantic Ocean ◽  
Global Scale ◽  
Data Set ◽  
Geographical Regions ◽  
Tropopause Region ◽  
Passenger Aircraft

IAGOS (In-service Aircraft for a Global Observing System) performs long-term routinein situobservations of atmospheric chemical composition (O3, CO, NOx, NOy, CO2, CH4), water vapour, aerosols, clouds, and temperature on a global scale by operating compact instruments on board of passenger aircraft. The unique characteristics of the IAGOS data set originate from the global scale sampling on air traffic routes with similar instrumentation such that the observations are truly comparable and well suited for atmospheric research on a statistical basis. Here, we present the analysis of 15 months of simultaneous observations of relative humidity with respect to ice (RHice) and ice crystal number concentration in cirrus (Nice) from July 2014 to October 2015. The joint data set of 360 hours of RHice–Niceobservations in the global upper troposphere and tropopause region is analysed with respect to the in-cloud distribution of RHiceand related cirrus properties. The majority of the observed cirrus is thin withNice< 0.1 cm−3. The respective fractions of all cloud observations range from 90% over the mid-latitude North Atlantic Ocean and the Eurasian Continent to 67% over the subtropical and tropical Pacific Ocean. The in-cloud RHicedistributions do not depend on the geographical region of sampling. Types of cirrus origin (in situorigin, liquid origin) are inferred for differentNiceregimes and geographical regions. Most importantly, we found that in-cloud RHiceshows a strong correlation toNicewith slightly supersaturated dynamic equilibrium RHiceassociated with higherNicevalues in stronger updrafts.

scholarly journals Total column CO<sub>2</sub> measurements at Darwin, Australia – site description and calibration against in situ aircraft profiles

2010 ◽  
Vol 3 (2) ◽  
pp. 989-1021 ◽  
Author(s):  
N. M. Deutscher ◽  
D. W. T. Griffith ◽  
G. W. Bryant ◽  
P. O. Wennberg ◽  
G. C. Toon ◽  
...  
Keyword(s):  
Nir Spectroscopy ◽  
Solar Observatory ◽  
Total Carbon ◽  
Relative Precision ◽  
Mixing Ratios ◽  
Clear Sky ◽  
The World ◽  
Total Column ◽  
Good Agreement

Abstract. An automated Fourier Transform Spectroscopic (FTS) solar observatory was established in Darwin, Australia in August 2005. The laboratory is part of the Total Carbon Column Observing Network, and measures atmospheric column abundances of CO2 and O2 and other gases. Measured CO2 columns were calibrated against integrated aircraft profiles obtained during the TWP-ICE campaign in January–February 2006, and show good agreement with calibrations for a similar instrument in Park Falls, Wisconsin. A clear-sky low airmass relative precision of 0.1% is demonstrated in the CO2 and O2 retrieved column-averaged volume mixing ratios. The 1% negative bias in the FTS XCO2 relative to the World Meteorological Organization (WMO) calibrated in situ scale is within the uncertainties of the NIR spectroscopy and analysis.

GEOPHYSICAL ACTIVITY IN 1954

Geophysics ◽  
1955 ◽  
Vol 20 (3) ◽  
pp. 654-670 ◽  
Author(s):  
Sigmund Hammer
Keyword(s):  
United States ◽  
Middle East ◽  
World Wide ◽  
Far East ◽  
Geophysical Methods ◽  
The United States ◽  
Global Scale ◽  
The Far East ◽  
Almost Everywhere ◽  
The World

Geophysical activity in explorations for petroleum on a global scale in 1954 was 6.3% lower than the record high of 1953. Notable increases in geophysical effort in Europe, the Middle East, and the Far East were not sufficient to overcome the very substantial decreases in the United States and Canada. The reduction occurred mainly in seismic operations, which decreased globally by 8.4%. Gravity activity was on the increase almost everywhere with the world‐wide rise of 7.1%. Magnetic and miscellaneous other geophysical methods also showed moderate increases in the neighborhood of one percent.

scholarly journals Tracing troposphere-to-stratosphere transport above a mid-latitude deep convective system

2004 ◽  
Vol 4 (3) ◽  
pp. 741-756 ◽  
Author(s):  
M. I. Hegglin ◽  
D. Brunner ◽  
H. Wernli ◽  
C. Schwierz ◽  
O. Martius ◽  
...  
Keyword(s):  
Potential Vorticity ◽  
Deep Convection ◽  
Potential Temperature ◽  
Western Mediterranean ◽  
Convective System ◽  
Air Masses ◽  
Backward Trajectories ◽  
Mixing Ratios ◽  
Stratospheric Intrusion ◽  
Tropopause Region

Abstract. Within the project SPURT (trace gas measurements in the tropopause region) a variety of trace gases have been measured in situ in order to investigate the role of dynamical and chemical processes in the extra-tropical tropopause region. In this paper we report on a flight on 10 November 2001 leading from Hohn, Germany (52ºN) to Faro, Portugal (37ºN) through a strongly developed deep stratospheric intrusion. This streamer was associated with a large convective system over the western Mediterranean with potentially significant troposphere-to-stratosphere transport. Along major parts of the flight we measured unexpectedly high NOy mixing ratios. Also H2O mixing ratios were significantly higher than stratospheric background levels confirming the extraordinary chemical signature of the probed air masses in the interior of the streamer. Backward trajectories encompassing the streamer enable to analyze the origin and physical characteristics of the air masses and to trace troposphere-to-stratosphere transport. Near the western flank of the intrusion features caused by long range transport, such as tropospheric filaments characterized by sudden drops in the O3 and NOy mixing ratios and enhanced CO and H2O can be reconstructed in great detail using the reverse domain filling technique. These filaments indicate a high potential for subsequent mixing with the stratospheric air. At the south-western edge of the streamer a strong gradient in the NOy and the O3 mixing ratios coincides very well with a sharp gradient in potential vorticity in the ECMWF fields. In contrast, in the interior of the streamer the observed highly elevated NOy and H2O mixing ratios up to a potential temperature level of 365 K and potential vorticity values of maximum 10 PVU cannot be explained in terms of resolved troposphere-to-stratosphere transport along the backward trajectories. Also mesoscale simulations with a High Resolution Model reveal no direct evidence for convective H2O injection up to this level. Elevated H2O mixing ratios in the ECMWF and HRM model are seen only up to about tropopause height at 340 hPa and 270hPa, respectively, well below flight altitude of about 200 hPa. However, forward tracing of the convective influence as identified by satellite brightness temperature measurements and counts of lightning strokes shows that during this part of the flight the aircraft was closely following the border of an air mass which was heavily impacted by convective activity over Spain and Algeria. This is evidence that deep convection at mid-latitudes may have a large impact on the tracer distribution of the lowermost stratosphere reaching well above the thunderstorms anvils as claimed by recent studies using cloud-resolving models.

Salinization sources and management strategies in South Africa

2020 ◽  
Author(s):  
Maria Elenius ◽  
Alena Bartosova ◽  
Jude Musuuza ◽  
Berit Arheimer
Keyword(s):  
South Africa ◽  
World Wide ◽  
River Flow ◽  
Management Strategies ◽  
Open Data ◽  
Water Source ◽  
Global Scale ◽  
Soil Salinization ◽  
Mitigation Strategies ◽  
The World

&lt;p&gt;Irrigation practices of various kinds are used in farming all over the world. Especially in cases of over-irrigation and inadequate drainage, evaporation losses can be high and lead to accumulation of minerals in the soils. Water uptake in crops is driven by osmosis, and as such it is reduced or diminished when salt concentrations in the soil water increase. Today, approximately 10 % of irrigated land worldwide has faced diminished production due to salinization, and losses increase every year. There is also concern that global warming can deteriorate production further due to increased evaporation, which should be considered in the light of increasing crop demands with population growth. There is therefore pressing concern to study effects and measures on a global scale.&lt;/p&gt;&lt;p&gt;Continental to global scale hydrological models have emerged in recent years as tools for flood forecasting and estimation of dynamic water fluxes. HYPE is a catchment-based model that simulates rainfall-runoff as well as water quality processes. Recently, an application was developed based on HYPE that covers almost the entire globe, World Wide HYPE (Arheimer et al., 2019). This tool also has great potential for future global assessments of soil salinization under different scenarios.&lt;/p&gt;&lt;p&gt;In this work, a salinization routine was developed in HYPE, whereby salt components follow all main natural hydrological pathways as well as irrigation using groundwater or river flow as a water source. Equilibrium reactions, complexation and cation exchange determine the distribution between dissolved and solid states in the soil. A semi-arid catchment in South Africa with salinization issues (the Crocodile River, Mpumalanga province) was chosen for code development, calibration and verification. Evaluations were based on comparison of simulated and observed mineral concentrations in rivers and groundwater. The model was also tested for all of South Africa.&lt;/p&gt;&lt;p&gt;Detailed analyses of the soil salinity processes were carried out for the Crocodile River catchment. Results show the sensitivity of salinization to hydrological parameters such as recession coefficients, infiltration capacities and macropore flow. This will guide future calibration of the World Wide HYPE model setup. Assessment of the major processes and sources of salinization is performed, and mitigation strategies such as irrigation control and drainage management are tested. Possible regionalization of parameters for global salinization modeling is also suggested based on the results.&lt;/p&gt;&lt;p&gt;Arheimer, B., Pimentel, R., Isberg, K., Crochemore, L., Andersson, J. C. M., Hasan, A., and Pineda, L. (accepted). Global catchment modelling using World-Wide HYPE (WWH), open data and stepwise parameter estimation, Hydrol. Earth Syst. Sci, https://doi.org/10.5194/hess-2019-111, in press, 2019&lt;/p&gt;

scholarly journals Total column CO<sub>2</sub> measurements at Darwin, Australia – site description and calibration against in situ aircraft profiles

2010 ◽  
Vol 3 (4) ◽  
pp. 947-958 ◽  
Author(s):  
N. M. Deutscher ◽  
D. W. T. Griffith ◽  
G. W. Bryant ◽  
P. O. Wennberg ◽  
G. C. Toon ◽  
...  
Keyword(s):  
Nir Spectroscopy ◽  
Solar Observatory ◽  
Total Carbon ◽  
Relative Precision ◽  
Mixing Ratios ◽  
Clear Sky ◽  
The World ◽  
Total Column ◽  
Good Agreement

Abstract. An automated Fourier Transform Spectroscopic (FTS) solar observatory was established in Darwin, Australia in August 2005. The laboratory is part of the Total Carbon Column Observing Network, and measures atmospheric column abundances of CO2 and O2 and other gases. Measured CO2 columns were calibrated against integrated aircraft profiles obtained during the TWP-ICE campaign in January–February 2006, and show good agreement with calibrations for a similar instrument in Park Falls, Wisconsin. A clear-sky low airmass relative precision of 0.1% is demonstrated in the CO2 and O2 retrieved column-averaged volume mixing ratios. The 1% negative bias in the FTS XCO2 relative to the World Meteorological Organization (WMO) calibrated in situ scale is within the uncertainties of the NIR spectroscopy and analysis.

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