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SOLAS OSC, 5.6-10, 2012, Cle Elum, WA, USA. Correlation of Asian dust with chlorophyll and primary productivity in North Pacific Ocean. Huiwang Gao (hwgao@ouc.edu.cn) Tan Saichun (sctan@mail.iap.ac.cn) Xiaohong Yao (xhyao@ouc.edu.cn) Jinhui Shi (engroup@ouc.edu.cn).
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SOLAS OSC, 5.6-10, 2012, Cle Elum, WA, USA Correlation of Asian dust with chlorophyll and primary productivity in North Pacific Ocean Huiwang Gao (hwgao@ouc.edu.cn) Tan Saichun (sctan@mail.iap.ac.cn) Xiaohong Yao (xhyao@ouc.edu.cn) Jinhui Shi (engroup@ouc.edu.cn) Ocean University of China
Main routes of dust transport (arrows) and locations of the world’s major deserts. The magnitudes of dust emission from different regions are given in Mt and indicated using bars and the depositions to the oceans are also given in Mt and indicated by thick arrows (Shao et al., Aeolian Research, 2011)
Principal ranges of the two major global dust transport systems. • The African dust system (red–orange) has a strong seasonal component • The Asian dust system (yellow) exports dust primarily during the spring Kellogg et al., Trends in ecology & evolution 2006
Studies that are underlined denote a relationship between dust and the biota, those that are not underlined denote that no relationship was reported. The underlined studies that are also overlined indicate that they have in subsequent re-analysis to be found to have misattributed the causes of the biological response to dust supply, for example the modelling study of Ridgewell (16) attributed high chlorophyll in the vicinity of the Kerguelen Plateau to be due to dust from South Africa, this region is characterised by high internal wave activity and a marine iron supply (Blain et al., 2007). Boyd et al., Marine Chemistry, 2010
Distribution of dust-event frequency, fDE, derived from the meteorological records of the 5-yr period between 27 May 1998 and 26 May 2003. • Four regions of frequent dust events, i.e., the Tarim Basin, the Gobi region , the Hexi Corridor and the Indian Subcontinent, are denoted with A, B, C and D, respectively. Shao and Dong, Global and Planetary Change, 2006
Dust storm in Jiuquan, Gansu A dust rain in Beijing, 2006 20kg per capita
Monthly Asian dust-event frequency (bars) and strong-wind (larger than 6.5 m s−1) frequency (solid line with full dots) averaged over the period of Jan 1993–Dec 2001 (Kurosaki and Mikami, 2003).
The annual total dry deposition of dust is found to be 101.4 in the dust source region, 7.8 in the Yellow Sea, 6.5 in the Korean peninsula and 2.1 in the East Sea. • Over the Yellow Sea the wet deposition contributes to 59% of the annual total deposition of dust (19.0) and over the East Sea/Japan Sea it contributes to 80% of the annual total deposition (10.7). Park et al., Science of the Total Environment, 2010
(1) A phytoplankton bloom in the Yellow Sea in 2007 following a dust storm accompanied by precipitation. Rainfall: 5-15mm/day in YS
A bloom was observed in the southern Yellow Sea on April 4~5 in a cruise, just several days after the dust event
Blooms were observed on these stations R/V Beidou(北斗号)
Table 1. Estimated dry and wet deposition fluxes for Fe, P, and inorganic nitrogen (TIN-N) over the Yellow Sea (mg m2 ) Shi et al., submitted to JGR
Table 2. Dust deposition and nutrients assimilation by the phytoplankton Upwelling fluxes of NO3-and PO43- were also calculated to be 4250 mol m-2d-1 and 240 mol m-2d-1 which are higher than those in normal days.
Chemical components & Chl.a in the surface water in SYS *Fe, DIN and DIP increments were estimated by the ratios with dissolved Al in aerosols
Table 3. Causality test for atmospheric deposition and primary production The denotation ***, ** and * means that the null hypothesis on non-Granger causality is rejected at the 1%, 5% and 10% significance level, respectively.
(2) Correlation of Asian dust with chlorophyll and primary productivity in YS from 1998 to 2008
The yearly variations of dust frequency (days per year), annual average Chl a (SeaWiFS, MODIS/AQUA ) concentration and OPP in the south Yellow Sea and East China Sea. Tan et al., JGR, 2011
Annual variations of bloom frequency and average days with AI (TOMS) ≥ 2 in the coastal seas of China including Bohai sea, Yellow sea and East China sea. Granger causality test shows the significant relationship between them. Tan et al., JGR, 2011
(3) Variability of correlation between Asian dust storms and Chla in the Pacific Map of the study sea areas in the Pacific Ocean. Tan et al., Submitted to GRL
Averaged occurrence frequency of dust storms (days per year)
The correlation between monthly chlorophyll a concentration(Sea WiFS Level-3) (mg m-3) in the six sea areas and monthly dust frequency (days per month) for the period from September 1997 to December 2007. The minimum contour is 0.2 with significance level of 0.05.
Movement routes of Asian-dust aerosols to the sea in 2000–2002. Zhang and Gao, AE, 2007
Back trajectory ensemble of Asian dust for Pacific Ocean from 10 May to 7 May 2007 using HYSPLIT model for altitude 6500m. Su and Toon, Atmos. Chem. Phys, 2011
PAPA KNOT ALOHA Asian dust events have changed the nutrients structure ( ), enhanced the biomass( ) even initiated algae bloom( ) in north Pacific Ocean
Summary • Asian dust events sometimes can initiate algae bloom in coastal seas (YS and ECS) by nutrients supply. • The correlations between chlorophyll a concentration and occurrence frequency of dust storms show Asian dust from different sources have varied impacts on bio-activities from marginal seas to the Pacific Ocean. • Further studies are critical to understand the reasons behind the correlations not only by limiting nutrient supply (based on Redfield ratio), and by considering the synergistic enhancement or inhibition of multi-chemicals from dust deposition, probably like the effects of Chinese herbs on body health.
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Estimates of atmospheric deposition of (a) N (NDep), (b) P (PDep), and (c) Fe (FeDep) to the global. Okin et al., GBC, 2011
Times series of TDI and GDI for the period of 1960-2004 Wang et al., AE, 2008 Days of strong dust storm, dust storm and blowing dust in China from 2000 to 2008. Zhang et al., Particuology, 2010
Global transported dust storm The dust originated from Taklimakan Desert during May 8-9, 2007 transports one full circuit around the global in approximately 13 days. Mean speed of dust transportation is about 2000km/day (Uno et al., 2009)