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Rainfall Variability over Zimbabwe and its relation to large-scale atmosphere-ocean processes
Mamombe Vimbai - 이화여자대학교 대학원, 2016For Zimbabwe, where rain fed agriculture is the backbone of the economy, the importance of accurate rainfall seasonal forecasts cannot be overemphasized (Makarau and Jury, 1997). In fact, extremes in interseasonal variability of rainfall can significantly complicate human livelihoods. In addition, there have been predictions of increased precipitation variability and hydro-meteorological hazards such as floods, droughts, and erratic rainfall due to global warming (Field et al., 2014; Mushore, 2013a). Thus, detailed understanding of the major contributors to the rainfall variability over Zimbab ...
Published by: 이화여자대학교 대학원 ; 2016
For Zimbabwe, where rain fed agriculture is the backbone of the economy, the importance of accurate rainfall seasonal forecasts cannot be overemphasized (Makarau and Jury, 1997). In fact, extremes in interseasonal variability of rainfall can significantly complicate human livelihoods. In addition, there have been predictions of increased precipitation variability and hydro-meteorological hazards such as floods, droughts, and erratic rainfall due to global warming (Field et al., 2014; Mushore, 2013a). Thus, detailed understanding of the major contributors to the rainfall variability over Zimbabwe would help in the development of mitigatory measures against the effects of extreme weather events.
The aim of this study is to identify significant climate factors that are associated with interseasonal variations in rainfall over Zimbabwe. Observational studies of the possible relationships between rainfall, global SST anomalies and synoptic scale atmospheric features were carried out. The investigation is mainly centered on the large scale circulation acclimatization to SST forcing andthe resultant rainfall changes. This is expected to make profound contributions to seasonal rainfall forecasting techniques around the country.Empirical orthogonal function.Notes: If you wish to download the full text, please contact library(at)wmo.int (Please replace (at) by @).
Language(s): English
Format: Digital (Available online for logged-in users)Tags: Precipitation ; Ocean-atmosphere interaction ; Research ; Zimbabwe ; Thesis - WMO Fellowship Division
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66 - February 2012 - A method for estimating the sea-air CO2 flux in the Pacific Ocean
is an issue of 気象研究所技術報告. Meteorological Research Institute, 2012In this technical report, we describe a newly developed method for evaluating monthly fields of oceanic pCO2 and the subsequent temporal variations of the sea-air CO2 flux over extensive regions of the North and South Pacific by using synthesized observational data. The application of this method is expected to contribute to understanding of future changes in the ocean carbon sink and the ocean's role in controlling the rate of atmospheric CO2 increase.
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Available online: http://www.mri-jma.go.jp/Publish/Technical/DATA/VOL_66/tec_rep_mri_66.pdf
In this technical report, we describe a newly developed method for evaluating monthly fields of oceanic pCO2 and the subsequent temporal variations of the sea-air CO2 flux over extensive regions of the North and South Pacific by using synthesized observational data. The application of this method is expected to contribute to understanding of future changes in the ocean carbon sink and the ocean's role in controlling the rate of atmospheric CO2 increase.
Language(s): English
Format: Digital (Free), Hard copyTags: Observations ; Ocean-atmosphere interaction ; Carbon dioxide (CO2) ; Pacific Ocean ; Region V - South-West Pacific
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GAW Report, 203. The Atmospheric Input of Chemicals to the Ocean
World Meteorological Organization (WMO) ; International Maritime Organization (IMO); Food and Agriculture Organization (FAO); et al. - WMO, 2012The atmospheric input of chemicals to the ocean is closely related to a number of important global change issues. The increasing input of atmospheric anthropogenic nitrogen species to much of the ocean may cause a low level fertilization of the ocean that could result in an increase in marine 'new' productivity of up to ~3% and thus impact carbon drawdown from the atmosphere. However, the increase in nitrogen inputs are also likely to increase the formation of nitrous oxide in the ocean. The increased emission of this powerful greenhouse gas will partially offset the climate forcing impact res ...
World Meteorological Organization (WMO) ; International Maritime Organization ; Food and Agriculture Organization (Rome, Italia) ; United Nations Educational, Scientific and Cultural Organization ; Intergovernmental Oceanographic Commission ; International Atomic Energy Agency (Vienna, Austria) ; United Nations ; United Nations Environment Programme ; United Nations Development Programme
Published by: WMO ; 2012The atmospheric input of chemicals to the ocean is closely related to a number of important global change issues. The increasing input of atmospheric anthropogenic nitrogen species to much of the ocean may cause a low level fertilization of the ocean that could result in an increase in marine 'new' productivity of up to ~3% and thus impact carbon drawdown from the atmosphere. However, the increase in nitrogen inputs are also likely to increase the formation of nitrous oxide in the ocean. The increased emission of this powerful greenhouse gas will partially offset the climate forcing impact resulting from the increase in carbon dioxide drawdown produced by N fertilization. Similarly, much of the oceanic iron, which is a limiting nutrient in many areas of the ocean, originates from the atmospheric input of minerals as a result of the long-range transport of mineral dust from continental regions. The increased supply of soluble phosphorus from atmospheric anthropogenic sources (through large-scale use in fertilizers) may also have a significant impact on surface-ocean biogeochemistry, but estimates are highly uncertain. While it is possible that the inputs of sulphur and nitrogen oxides from the atmosphere can add to the rates of ocean acidification occurring due to rising levels of carbon dioxide, there is too little information on these processes to assess the potential impact. These inputs may be particularly critical in heavily trafficked shipping lanes and in ocean regions proximate to highly industrialized land areas. Other atmospheric substances may also have an impact on the ocean, in particular lead, cadmium, and POPs. GESAMP initiated Working Group 38, The Atmospheric Input of Chemicals to the Ocean, to address these issues.
Collection(s) and Series: GAW Report- No. 203
Language(s): English
Format: Digital (Free), Hard copyTags: Oceans ; Atmospheric chemistry ; Ocean-atmosphere interaction ; Global Atmosphere Watch Programme (GAW) ; GESAMP 84
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Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 7. Miyazaki Y.; Kawamura K.; Jung J.; et al. - Copernicus GmbH, 2011Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON) and organic carbon (OC) as well as isotopic ratios of total nitrogen (TN) and total carbon (TC). Increased concentrations of methanesulfonic acid (MSA) and diethylammonium (DEA+) at 40–44° N and subtropical regions (10–20° N) together with averaged satellite chlorophyll-a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited incre ...
[article]Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific
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Available online: http://dx.doi.org/10.5194/acp-11-3037-2011
Y. Miyazaki ; K. Kawamura ; J. Jung ; H. Furutani ; M. Uematsu
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 7 [04/01/2011] . - p.3037-3049Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON) and organic carbon (OC) as well as isotopic ratios of total nitrogen (TN) and total carbon (TC). Increased concentrations of methanesulfonic acid (MSA) and diethylammonium (DEA+) at 40–44° N and subtropical regions (10–20° N) together with averaged satellite chlorophyll-a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION) was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios (δ13C) indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C showed higher values (from −22 to −20‰) when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC) ratios tended to increase with increasing local wind speeds, indicating that sea-to-air emissions of ON via sea spray contribute significantly to the marine organic aerosols over the study region.
Language(s): English
Format: Digital (Free)Tags: Aerosols ; Nitrogen ; Ocean-atmosphere interaction ; Observations ; Pacific Ocean ; Region V - South-West Pacific
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Pseudo steady states of HONO measured in the nocturnal marine boundary layer: a conceptual model for HONO formation on aqueous surfaces
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 7. Wojtal P.; Halla J.D.; McLaren R. - Copernicus GmbH, 2011A complete understanding of the formation mechanism of nitrous acid (HONO) in the ambient atmosphere is complicated by a lack of understanding of processes occurring when aqueous water is present. We report nocturnal measurements of HONO, SO2 and NO2 by differential optical absorption spectroscopy over the ocean surface in a polluted marine environment. In this aqueous environment, we observed reproducible pseudo steady states (PSS) of HONO every night, that are fully formed shortly after sunset, much faster than seen in urban environments. During the PSS period, HONO is constant with time, in ...
[article]Pseudo steady states of HONO measured in the nocturnal marine boundary layer: a conceptual model for HONO formation on aqueous surfaces
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Available online: http://dx.doi.org/10.5194/acp-11-3243-2011
in Atmospheric Chemistry and Physics (ACP) > Vol. 11. N° 7 [04/01/2011] . - p.3243-3261A complete understanding of the formation mechanism of nitrous acid (HONO) in the ambient atmosphere is complicated by a lack of understanding of processes occurring when aqueous water is present. We report nocturnal measurements of HONO, SO2 and NO2 by differential optical absorption spectroscopy over the ocean surface in a polluted marine environment. In this aqueous environment, we observed reproducible pseudo steady states (PSS) of HONO every night, that are fully formed shortly after sunset, much faster than seen in urban environments. During the PSS period, HONO is constant with time, independent of air mass source and independent of the concentration of NO2. The independence of HONO on the concentration of NO2 implies a 0° order formation process, likely on a saturated surface, with reversible partitioning of HONO to the gas phase, through vaporization and deposition to the surface. We observed median HONO/NO2 ratios starting at 0.13 at the beginning of the PSS period (with an apparent lower bound of 0.03), rising to median levels of ~0.30 at the end of the PSS period (with an upper bound >1.0). The implication of these numbers is that they suggest a common surface mechanism of HONO formation on terrestrial and aqueous surfaces, with an increase in the HONO/NO2 ratio with the amount of water available at the surface. The levels of HONO during the nocturnal PSS period are positively correlated with temperature, consistent with a partitioning of HONO from the surface to the gas phase with an apparent enthalpy of vaporization of ΔHSNL (HONO)=55.5±5.4 kJ mol−1. The formation mechanism on aqueous surfaces is independent of relative humidity (RH), despite observation of a negative HONO-RH correlation. A conceptual model for HONO formation on ambient aqueous surfaces is presented, with the main elements being the presence of a surface nanolayer (SNL), highly acidic and saturated with N(IV) precursors, production of HNO3, that diffuses to underlying water layers, and HONO, which partitions reversibly between the SNL and the gas phase. Implications of the conceptual model are discussed.
Language(s): English
Format: Digital (Free)Tags: Ocean-atmosphere interaction ; Oceans ; Water pollution ; Research
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Ozone production in remote oceanic and industrial areas derived from ship based measurements of peroxy radicals during TexAQS 2006
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Sommariva R.; Brown S.S.; Roberts J.M.; et al. - Copernicus GmbH, 2011During the Texas Air Quality Study II (TexAQS 2006) campaign, a PEroxy Radical Chemical Amplifier (PERCA) was deployed on the NOAA research vessel R/V Brown to measure total peroxy radicals (HO2+Σ RO2). Day-time mixing ratios of HO2+Σ RO2 between 25 and 110 ppt were observed throughout the study area – the Houston/Galveston region and the Gulf coast of the US – and analyzed in relation to measurements of nitrogen oxides, volatile organic compounds (VOC) and photolysis rates to assess radical sources and sinks in the region.
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Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Johnson M.S.; Meskhidze N.; Kiliyanpilakkil V.P.; et al. - Copernicus GmbH, 2011The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO). Model simulations for the atmospheric transport and deposition of mineral du ...
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Distribution and air-sea exchange of mercury (Hg) in the Yellow Sea
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Ci Z.J.; Zhang X.S.; Wang Z.W.; et al. - Copernicus GmbH, 2011The Yellow Sea, surrounded by East China and the Korea Peninsula, is a potentially important receptor for anthropogenic mercury (Hg) emissions from East Asia. However, there is little documentation about the distribution and cycle of Hg in this marine system. During the cruise covering the Yellow Sea in July 2010, gaseous elemental mercury (GEM or Hg(0)) in the atmosphere, total Hg (THg), reactive Hg (RHg) and dissolved gaseous mercury (DGM, largely Hg(0)) in the waters were measured aboard the R/V Kexue III. The mean (±SD) concentration of GEM over the entire cruise was 2.61 ± 0.50 ng m−3 (ra ...
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On the impacts of phytoplankton-derived organic matter on the properties of the primary marine aerosol – Part 2: Composition, hygroscopicity and cloud condensation activity
Atmospheric Chemistry and Physics (ACP), Vol. 11. N° 3. Fuentes E.; Coe H.; Green D.; et al. - Copernicus GmbH, 2011The effect of nanogel colloidal and dissolved organic matter <0.2 μm, secreted by marine biota, on the hygroscopic growth and droplet activation behaviour of the primary marine aerosol was studied. Seawater proxies were prepared by the combination of artificial seawater devoid of marine organics and natural seawater enriched in organic exudate released by laboratory-grown phytoplankton cultures, as described in a companion paper. The primary aerosol was produced by bubble bursting, using a plunging multijet system as an aerosol generator.
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CAWCR technical report, 40. Comparison of techniques for the calibration of coupled model forecasts of Murray Darling Basin seasonal mean rainfall
Charles Andrew; Hendon Harry H.; Wang Q.J.; et al. - Centre for Australian Weather and Climate Research, 2011Ensemble forecasts of South Eastern Australian rainfall from POAMA 1.5, a coupled oceanatmosphere dynamical model based seasonal prediction system run experimentally at the Bureau of Meteorology, tend to be under dispersed leading to overconfident probability forecasts. The poor reliability of seasonal forecasts based on dynamical coupled models is a barrier to their adoption as official outlooks by the Bureau of Meteorology. One approach to correcting this problem is model calibration, in which the probability distribution produced by the model is adjusted in light of available information ab ...
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GAW Report, 202. Workshop on Modelling and Observing the Impacts of Dust Transport/Deposition on Marine Productivity
In this report we evaluate the state-of-art knowledge and uncertainties regarding the deposition of dust on the ocean and its mineralogical composition provided by models and measurement datasets. Global climate models were recently intercompared by Huneeus et al. (2011) using results from the AEROCOM model intercomparison. The deposition calculations from these global models are frequently used as input for biological productivity calculations. A model measurement comparison (Huneeus, 2011) shows that global models do reproduce the observed data over several orders of magnitude. However, the ...
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Blue carbon policy framework 2.0 : based on the discussion of the International Blue Carbon Policy Working Group
Development and implementation of blue carbon-based activities now requires strategic policy and incentive mechanisms to achieve coastal conservation, restoration and sustainable use, and provide disincentives to drain or damage coastal systems. A first effort to develop such a strategic program was set out in the first edition of the Blue Carbon Policy Framework. Based on additional information and current progress a revised Blue Carbon Policy Framework 2.0 has now been developed. It updates the previous version and adds a detailed coordinated program of policy objectives and activities. It o ...
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Regime Behavior in the Sea Surface Temperature-Cloud Radiative Forcing Relationships over the Pacific Cold Tongue Region
Atmospheric and Oceanic Science Letters, Volume 3 Number 5. Wu Chun-Qiang; Zhou Tian-Jun; De-Zheng Xiao-Li - Science Press, 2010Previous analyses on the estimates of water vapor and cloud-related feedbacks in the tropics usually use observations over the Earth Radiation Budget Experiment (ERBE) period (1985–89). To examine the sample dependence of previous estimates, the authors extend the analysis to two additional periods: 1990–94 and 1995–99. The results confirm our hypothesis, i.e., the values of the feedbacks depend on the period of data coverage. The differences in the feedbacks from cloud radiative forcings (CRFs) estimated from the three periods are particularly significant. Two possible causes for these differ ...
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Marine Atmospheric Boundary Layers Associated with Summer Monsoon Onset over the South China Sea in 1998
Atmospheric and Oceanic Science Letters, Volume 3 Number 5. Wang Dong-Xiao; Zhou Wen; Yu Xiao-Li; et al. - Science Press, 2010The variations of the marine atmospheric boundary layer (MABL) associated with the South China Sea Summer Monsoon were examined using the Global Positioning System (GPS) sounding datasets obtained four times daily during May-June 1998 on board Research Vessels Kexue 1 and Shiyan 3. The MABL height is defined as the height at the lowest level where virtual potential temperature increases by 1 K from the surface. The results indicate that the MABL height decreased over the northern South China Sea (SCS) and remained the same over the southern SCS, as sea surface temperature (SST) fell for the no ...
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Diapycnal Mixing in Transient Responses of the Atlantic Meridional Overturning Circulation in an Enhanced Freshwater Perturbation Experiment
Atmospheric and Oceanic Science Letters, Volume 3 Number 4. Yu Lei; Gao Yong-Qi; Helge Drange; et al. - Science Press, 2010It has been reported recently that the simulated Atlantic meridional overturning circulation (AMOC) using the coupled Bergen climate model (BCM) showed initial intensity declines followed by gradual recoveries over a 150-year enhanced freshwater input experiment. Stratification-dependent oceanic diapycnal mixing has been hypothesized as a reason for the simulated recovery of the AMOC. This study investigated the role of diapycnal mixing in transient responses of simulated AMOCs. Our results showed that stratification-dependent diapycnal mixing can cause stronger upwelling of deep water in the ...
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