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| Titel |
Testing the relationship between the solar radiation dose and surface DMS concentrations using in situ data |
| VerfasserIn |
C. J. Miles, T. G. Bell, T. M. Lenton |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 9 ; Nr. 6, no. 9 (2009-09-28), S.1927-1934 |
| Datensatznummer |
250003995
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| Publikation (Nr.) |
 copernicus.org/bg-6-1927-2009.pdf |
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| Zusammenfassung |
| The proposed strong positive relationship between dimethylsulphide (DMS)
concentration and the solar radiation dose (SRD) received into the surface
ocean is tested using data from the Atlantic Meridional Transect (AMT)
programme. In situ, daily data sampled concurrently with DMS concentrations
is used for the component variables of the SRD (mixed layer depth, MLD,
surface insolation, I0, and a light attenuation coefficient, k) to
calculate SRDinsitu. This is the first time in situ data for all of
the components, including k, has been used to test the SRD-DMS relationship
over large spatial scales. We find a significant correlation (ρ=0.55
n=65 p<0.01) but the slope of this relationship
(0.006 nM/W m−2) is less than previously found at the global
(0.019 nM/W m−2) and regional scales (Blanes Bay, Mediterranean,
0.028 nM/W m−2; Sargasso Sea 0.017 nM/W m−2). The correlation
is improved (ρ=0.74 n=65 p<0.01) by replacing the in situ data
with an estimated I0 (which assumes a constant 50% removal of the top of
atmosphere value; 0.5×TOA), a MLD climatology and a fixed value for
k following previous work. Equally strong, but non-linear relationships are
also found between DMS and both in situ MLD (ρ=0.61 n=65
p<0.01) and the estimated I0 (ρ=0.73 n=65 p<0.01)
alone. Using a satellite-retrieved, cloud-adjusted surface UVA irradiance to
calculate a UV radiation dose (UVRD) with a climatological MLD also provides
an equivalent correlation (ρ=0.67 n=54 p<0.01) to DMS. With
this data, MLD appears the dominant control upon DMS concentrations and
remains a useful shorthand to prediction without fully resolving the
biological processes involved. However, the implied relationship between the
incident solar/ultraviolet radiation (modulated by MLD), and sea surface DMS
concentrations, is critical for closing a climate feedback loop. |
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