GESAMP 38/5
21 April 2011
ENGLISH ONLY
38th session
PLANNING OF GESAMP ACTIVITIES:
ATMOSPHERIC INPUT OF POLLUTANTS TO THE OCEANS
Report of the Chairman of Working Group 38
1
Since GESAMP 37, WMO continued to coordinate and guide the work on studying the
scientific issue of marine productivity as a result of nutrients deposited from the atmosphere. To
accomplish the related work, GESAMP Working Group 38 (WG 38) was charged with the
following tasks:
.1
Assessing the need for the development of new model and measurement
products for improving our understanding of the impacts of the atmospheric
deposition of nitrogen species and dust (iron) to the ocean;
.2
Reviewing the present information on the atmospheric deposition of phosphorus
species to both the marine and terrestrial environments, considering both natural
and anthropogenic sources, and evaluate the impact of atmospheric phosphorus
deposition on marine and terrestrial ecosystems. To consider whether such a
review of any other substance would be useful; and
.3
Cooperating with the WMO Sand and Dust Storm Warning Advisory and
Assessment System (SDS-WAS) and with the WMO Precipitation Chemistry
Data Synthesis and Community Project to evaluate the needs of the marine
community and assist in clearly articulating them in the development of these
WMO efforts.
2
Under Tasks 1 and 2, three separate papers/documents have been prepared that the
working group will write in the areas of phosphorus, nitrogen, iron and organic matter deposition
from the atmosphere to the ocean. The co-authors (members of the WG38) of these 3 papers
worked throughout the year gathering all the data and information necessary to complete these
papers. One paper has already been published 1 , while two are submitted for publication in
Geophysical Research Letters and are currently being reviewed.
3
Under Task 3, the work in the period 2010-2011 was focused to finalize the new global
assessment of the precipitation chemistry deposition. The WMO Precipitation Chemistry
Programme integrates measurements of WMO partners’ regional networks: EMEP (Europe),
DEBITS (Africa), EANET (East Asia), CAPMoN (Canada), and NADP (United States). The
integration includes ground-based measurements and atmospheric chemistry models to fill
gaps, especially over sea areas and in regions where generally there is lack of measurements
(e.g., in the southern hemisphere). The final version of this assessment, which is expected to
be published in a peer-review journal, reviews the state of the science on precipitation chemistry
regionally and globally, and presents the observed data for the 2000-2006 periods. The
1
Okin, G. S., A. R. Baker, I. Tegen, N. M. Mahowald, F. J. Dentener, R. A. Duce, J. N. Galloway, K. Hunter, M. Kanakidou, N.
Kubilay, J. M. Prospero, M. Sarin, V. Surapipith, M. Uematsu, and T. Zhu (2011), Impacts of atmospheric nutrient deposition on
marine productivity: roles of nitrogen, phosphorus, and iron, Global Biogeochem. Cycles, doi:10.1029/2010GB003858, in press.
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GESAMP 38/5
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assessment includes, among others, nitrogen, phosphorus and metals (such as Fe) –
components relevant for the air-sea exchange process and considered in the WG38 studies.
4
Based on the Task 3 requirements, an extension was agreed of the activities of Working
Group 38 for a period beyond 2010, with the aim of achieving a more detailed description of the
atmospheric transport and deposition process of iron- and phosphorus-carried minerals to the
ocean. Working Group 38 cooperated with the WMO SDS-WAS in order to exploit the already
existing modeling and observational capabilities of the SDS-WAS project. The collaboration
resulted in a meeting in March 2011 between the WG 38 and SDS-WAS communities
(“Workshop on Modeling and Observing the Impacts of Dust Transport/Deposition on Marine
Productivity”). The outcome of the meeting included advice as to how impacts of dust transport
on marine productivity can most profitably be addressed in the future activities of WMO and
GESAMP. The conclusions of the meeting are that the scientific communities should focus their
activities on:
.1
Improving the quantitative estimates of the geographical distribution of the
transport and deposition of mineral matter and its content to the ocean;
.2
Assessing of long-term mineral dust/Fe/P input to the ocean: In-situ observations
and marine response utilizing coupled atmospheric transport and ocean
biogeochemical modelling and remote-sensing; and
.3
Specifying test-bed regions for joint studies of the transport and deposition to the
ocean of mineral matter (Central Atlantic; North Pacific; Indian Ocean;
Mediterranean; others), utilizing SDS-WAS transport modelling.
5
Three reports were developed in these areas and, to date, these reports are still being
finalized. They will be presented at this session and also be submitted to WMO.
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