The uptake of dissolved inorganic nitrogen by phytoplankton is an important aspect of the nitrogen cycle of oceans. Here, we present nitrate (<svg     style="vertical-align:-3.3907pt;width:39.400002px;" id="M1" height="15.8375" version="1.1" viewBox="0 0 39.400002 15.8375" width="39.400002"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,11.55)"><path id="x4E" d="M719 650v-28q-43 -2 -62 -15t-22 -44q-6 -47 -6 -169v-403h-31l-426 524h-2v-251q0 -111 6 -169q4 -37 24 -50.5t72 -16.5v-28h-237v28q45 2 64.5 16t23.5 49q6 62 6 171v220q0 54 -3 68.5t-17 32.5q-16 19 -34.5 26.5t-54.5 10.5v28h147l418 -502h3v246q0 117 -7 166&#xA;q-4 34 -24.5 47t-73.5 15v28h236z" /></g><g transform="matrix(.017,-0,0,-.017,12.693,11.55)"><path id="x4F" d="M381 665q131 0 226.5 -93t95.5 -239q0 -158 -96 -253t-238 -95q-137 0 -231 95t-94 238q0 142 92.5 244.5t244.5 102.5zM359 629q-89 0 -151 -74.5t-62 -208.5q0 -141 69 -233t175 -92q90 0 150.5 74t60.5 211q0 152 -69 237.5t-173 85.5z" /></g>

            <g transform="matrix(.012,-0,0,-.012,25.388,15.637)"><path id="x33" d="M285 378v-2q65 -13 102 -54.5t37 -97.5q0 -57 -30.5 -104.5t-74 -75t-85.5 -42t-72 -14.5q-31 0 -59.5 11t-40.5 23q-19 18 -16 36q1 16 23 33q13 10 24 0q58 -51 124 -51q55 0 88 40t33 112q0 64 -39 96.5t-88 32.5q-29 0 -64 -11l-6 29q77 25 118 57.5t41 84.5&#xA;q0 45 -26.5 69.5t-68.5 24.5q-67 0 -120 -79l-20 20l43 63q51 56 127 56h1q66 0 107 -37t41 -95q0 -42 -31 -71q-22 -23 -68 -54z" /></g><g transform="matrix(.012,-0,0,-.012,31.725,3.4)"><path id="x2212" d="M535 230h-483v50h483v-50z" /></g>

        
    
</svg>) and ammonium (<svg     style="vertical-align:-3.27605pt;width:39.712502px;" id="M2" height="18.200001" version="1.1" viewBox="0 0 39.712502 18.200001" width="39.712502"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,14.05)"><use xlink:href="#x4E"/></g><g transform="matrix(.017,-0,0,-.017,12.693,14.05)"><path id="x48" d="M729 650v-28q-62 -5 -76 -19.5t-14 -75.5v-404q0 -62 13.5 -76t75.5 -19v-28h-268v28q65 5 79.5 19t14.5 76v199h-341v-199q0 -62 14 -76t76 -19v-28h-263v28q61 5 74.5 19t13.5 76v404q0 62 -14 76t-76 19v28h259v-28q-58 -5 -71 -19t-13 -76v-162h341v162&#xA;q0 61 -13.5 75.5t-72.5 19.5v28h261z" /></g>

            <g transform="matrix(.012,-0,0,-.012,25.712,18.137)"><path id="x34" d="M456 178h-96v-72q0 -51 12.5 -62.5t72.5 -16.5v-27h-256v27q65 5 78 17t13 62v72h-260v28q182 271 300 426h40v-407h96v-47zM280 225v295h-2q-107 -148 -196 -295h198z" /></g><g transform="matrix(.012,-0,0,-.012,32.05,5.887)"><path id="x2B" d="M535 230h-212v-233h-58v233h-213v50h213v210h58v-210h212v-50z" /></g>

        
    
</svg>) uptake rates in the northeastern Arabian Sea using <svg     style="vertical-align:-0.12283pt;width:24.799999px;" id="M3" height="15.9875" version="1.1" viewBox="0 0 24.799999 15.9875" width="24.799999"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.012,-0,0,-.012,.062,7.613)"><path id="x31" d="M384 0h-275v27q67 5 81.5 18.5t14.5 68.5v385q0 38 -7.5 47.5t-40.5 10.5l-48 2v24q85 15 178 52v-521q0 -55 14.5 -68.5t82.5 -18.5v-27z" /></g><g transform="matrix(.012,-0,0,-.012,5.774,7.613)"><path id="x35" d="M153 550l-26 -186q79 31 111 31q90 0 141.5 -51t51.5 -119q0 -93 -89 -166q-85 -69 -173 -71q-32 0 -61.5 11.5t-41.5 23.5q-18 17 -17 34q2 16 22 33q14 9 26 -1q61 -50 124 -50q60 0 93 43.5t33 104.5q0 69 -41.5 110t-121.5 41q-53 0 -102 -20l38 305h286l6 -8&#xA;l-26 -65h-233z" /></g>

            <g transform="matrix(.017,-0,0,-.017,12.112,15.775)"><use xlink:href="#x4E"/></g>

        
    
</svg> tracer technique. In this relatively underexplored region, productivity is high during winter due to supply of nutrients by convective mixing caused by the cooling of the surface by the northeast monsoon winds. Studies done during different months (January and late February-early March) of the northeast monsoon 2003 revealed a fivefold increase in the average euphotic zone integrated <svg     style="vertical-align:-3.3907pt;width:39.400002px;" id="M4" height="15.8375" version="1.1" viewBox="0 0 39.400002 15.8375" width="39.400002"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,11.55)"><use xlink:href="#x4E"/></g><g transform="matrix(.017,-0,0,-.017,12.693,11.55)"><use xlink:href="#x4F"/></g>

            <g transform="matrix(.012,-0,0,-.012,25.388,15.637)"><use xlink:href="#x33"/></g><g transform="matrix(.012,-0,0,-.012,31.725,3.4)"><use xlink:href="#x2212"/></g>

        
    
</svg> uptake from January (2.3&#x2009;mmolN <svg     style="vertical-align:-0.0pt;width:27.362499px;" id="M5" height="15.8375" version="1.1" viewBox="0 0 27.362499 15.8375" width="27.362499"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,15.775)"><path id="x6D" d="M797 0h-214v26q46 5 58 17.5t12 63.5v167q0 116 -88 116q-48 0 -112 -52q3 -18 3 -42v-195q0 -46 11 -58t53 -17v-26h-214v26q48 5 59.5 17t11.5 60v172q0 115 -88 115q-47 0 -109 -52v-235q0 -47 10 -59.5t48 -17.5v-26h-211v26q50 5 62.5 17t12.5 60v207q0 48 -9 59.5&#xA;t-52 18.5v23q79 14 139 41v-81q3 2 29 20.5t44 29.5q45 28 81 28t66 -22t46 -61q25 20 83 57q39 26 76 26q59 0 93 -40t34 -113v-193q0 -49 10.5 -60.5t54.5 -16.5v-26z" /></g>

            <g transform="matrix(.012,-0,0,-.012,13.987,7.613)"><use xlink:href="#x2212"/></g><g transform="matrix(.012,-0,0,-.012,20.972,7.613)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g>

        
    
</svg> <svg     style="vertical-align:-0.16379pt;width:22.424999px;" id="M6" height="16.049999" version="1.1" viewBox="0 0 22.424999 16.049999" width="22.424999"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,15.775)"><path id="x64" d="M517 51v-25q-101 -18 -155 -38v65l-61 -36q-50 -29 -78 -29q-68 0 -126.5 58t-58.5 155q0 103 77 175.5t180 72.5q36 0 67 -12v143q0 48 -11.5 58.5t-65.5 14.5v25q79 9 156 34v-597q0 -38 7.5 -48t36.5 -13zM362 85v275q-35 51 -103 51q-20 0 -40.5 -8.5t-42 -28&#xA;t-35 -57.5t-13.5 -89q0 -83 42 -130t96 -47q51 0 96 34z" /></g>

            <g transform="matrix(.012,-0,0,-.012,9.038,7.613)"><use xlink:href="#x2212"/></g><g transform="matrix(.012,-0,0,-.012,16.022,7.613)"><use xlink:href="#x31"/></g>

        
    
</svg>) to late February-early March (12.7&#x2009;mmolN <svg     style="vertical-align:-0.0pt;width:27.362499px;" id="M7" height="15.8375" version="1.1" viewBox="0 0 27.362499 15.8375" width="27.362499"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,15.775)"><use xlink:href="#x6D"/></g>

            <g transform="matrix(.012,-0,0,-.012,13.987,7.613)"><use xlink:href="#x2212"/></g><g transform="matrix(.012,-0,0,-.012,20.972,7.613)"><use xlink:href="#x32"/></g>

        
    
</svg> <svg     style="vertical-align:-0.16379pt;width:22.424999px;" id="M8" height="16.049999" version="1.1" viewBox="0 0 22.424999 16.049999" width="22.424999"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,15.775)"><use xlink:href="#x64"/></g>

            <g transform="matrix(.012,-0,0,-.012,9.038,7.613)"><use xlink:href="#x2212"/></g><g transform="matrix(.012,-0,0,-.012,16.022,7.613)"><use xlink:href="#x31"/></g>

        
    
</svg>). The <svg     style="vertical-align:-3.56265pt;width:11.0375px;" id="M9" height="16.6625" version="1.1" viewBox="0 0 11.0375 16.6625" width="11.0375"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,12.162)"><path id="x1D453" d="M619 670q0 -13 -9 -26t-18 -19q-13 -10 -25 2q-36 38 -66 38q-31 0 -54.5 -50t-45.5 -185h120l-20 -31l-107 -12q-23 -138 -57 -293q-27 -122 -55 -184.5t-75 -109.5q-60 -61 -114 -61q-25 0 -47.5 15t-22.5 31q0 17 31 44q11 8 20 -1q10 -11 31 -19t35 -8q26 0 47 19&#xA;q34 34 71 253l54 315h-90l-3 12l31 30h70q28 138 90 204q35 37 75 57.5t70 20.5q26 0 45 -14t19 -28z" /></g>

        
    
</svg>-ratio during January appeared to be affected by the winter cooling effect and increased by more than 50&#x25; from the southernmost station to the northern open ocean stations, indicating hydrographic and meteorological control. Estimates of <svg     style="vertical-align:-3.3907pt;width:39.400002px;" id="M10" height="15.8375" version="1.1" viewBox="0 0 39.400002 15.8375" width="39.400002"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,11.55)"><use xlink:href="#x4E"/></g><g transform="matrix(.017,-0,0,-.017,12.693,11.55)"><use xlink:href="#x4F"/></g>

            <g transform="matrix(.012,-0,0,-.012,25.388,15.637)"><use xlink:href="#x33"/></g><g transform="matrix(.012,-0,0,-.012,31.725,3.4)"><use xlink:href="#x2212"/></g>

        
    
</svg> residence time suggested that <svg     style="vertical-align:-3.3907pt;width:39.400002px;" id="M11" height="15.8375" version="1.1" viewBox="0 0 39.400002 15.8375" width="39.400002"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
    
        
            <g transform="matrix(.017,-0,0,-.017,.062,11.55)"><use xlink:href="#x4E"/></g><g transform="matrix(.017,-0,0,-.017,12.693,11.55)"><use xlink:href="#x4F"/></g>

            <g transform="matrix(.012,-0,0,-.012,25.388,15.637)"><use xlink:href="#x33"/></g><g transform="matrix(.012,-0,0,-.012,31.725,3.4)"><use xlink:href="#x2212"/></g>

        
    
</svg> entrained in the water column during January contributed to the development of blooms during late February-early March.

S. Kumar

R. Ramesh

R. M. Dwivedi

M. Raman

M. S. Sheshshayee

W. D'Souza

Nitrogen Uptake in the Northeastern Arabian Sea during Winter Cooling

Signals in data are often detected by analyzing anomaly field that is calculated by subtracting the mean value over a time length from the data.  Here we demonstrate that the anomaly calculation removes signals which satisfy that the ratio between the time length of the mean <svg style="vertical-align:-0.0pt;width:11.45px;" id="M1" height="11.6125" version="1.1" viewBox="0 0 11.45 11.6125" width="11.45" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,11.55)"><path id="x1D447" d="M649 676l-22 -187l-33 -2q3 56 -12 94q-8 20 -31.5 26.5t-86.5 6.5h-74l-90 -491q-4 -23 -6 -36.5t1 -25t7 -16.5t18 -9t27 -5t41 -3l-6 -28h-286l4 28q68 5 84 18.5t28 76.5l94 491h-55q-74 0 -100.5 -6t-41.5 -23q-24 -29 -54 -98l-32 1q32 98 53 188h22q7 -18 15 -22&#xA;t37 -4h417q23 0 33.5 5t25.5 21h23z" /></g></svg> and signals' period <svg style="vertical-align:-0.0pt;width:9.8249998px;" id="M2" height="11.175" version="1.1" viewBox="0 0 9.8249998 11.175" width="9.8249998" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,11.113)"><path id="x1D43F" d="M559 163q-23 -66 -68 -163h-474l6 26q62 4 79.5 19.5t28.5 75.5l78 409q7 35 8.5 49t-8 25t-24 13t-51.5 5l5 28h266l-6 -28q-65 -5 -79.5 -18t-25.5 -74l-76 -406q-10 -57 14 -75q12 -13 96 -13q93 0 126 29q41 40 76 109z" /></g></svg> is an integer (i.e., <svg style="vertical-align:-2.22493pt;width:28.15px;" id="M3" height="14.85" version="1.1" viewBox="0 0 28.15 14.85" width="28.15" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,12.012)"><use xlink:href="#x1D447" /></g><g transform="matrix(.017,-0,0,-.017,11.384,12.012)"><path id="x2F" d="M368 703l-264 -866h-60l265 866h59z" /></g><g transform="matrix(.017,-0,0,-.017,18.387,12.012)"><use xlink:href="#x1D43F" /></g></svg><svg style="vertical-align:-0.1638pt;width:23.362499px;" id="M4" height="7.9499998" version="1.1" viewBox="0 0 23.362499 7.9499998" width="23.362499" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><path id="x3D" d="M535 323h-483v50h483v-50zM535 138h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,14.749,7.675)"><path id="x1D45B" d="M495 86q-46 -47 -87 -72.5t-63 -25.5q-43 0 -16 107l49 210q7 34 8 50.5t-3 21t-13 4.5q-35 0 -109.5 -72.5t-115.5 -140.5q-21 -75 -38 -159q-50 -10 -76 -21l-6 8l84 340q8 35 -4 35q-17 0 -67 -46l-15 26q44 44 85.5 70.5t64.5 26.5q35 0 10 -103l-24 -98h2&#xA;q42 56 97 103.5t96 71.5q46 26 74 26q9 0 16 -2.5t14 -11.5t9.5 -24.5t-1 -44t-13.5 -68.5q-30 -117 -47 -200q-4 -19 -3.5 -25t6.5 -6q21 0 70 48z" /></g></svg> where <svg style="vertical-align:-0.1638pt;width:8.6625004px;" id="M5" height="7.9499998" version="1.1" viewBox="0 0 8.6625004 7.9499998" width="8.6625004" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D45B" /></g></svg> is an integer)  and retains other signals if the ratio is not an integer.  In climatic and other studies, the time length of the mean is usually chosen as <svg style="vertical-align:-0.0pt;width:47.1875px;" id="M6" height="11.6125" version="1.1" viewBox="0 0 47.1875 11.6125" width="47.1875" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,11.55)"><use xlink:href="#x1D447" /></g><g transform="matrix(.017,-0,0,-.017,16.092,11.55)"><use xlink:href="#x3D" /></g><g transform="matrix(.017,-0,0,-.017,30.796,11.55)"><path id="x31" d="M384 0h-275v27q67 5 81.5 18.5t14.5 68.5v385q0 38 -7.5 47.5t-40.5 10.5l-48 2v24q85 15 178 52v-521q0 -55 14.5 -68.5t82.5 -18.5v-27z" /></g><g transform="matrix(.017,-0,0,-.017,38.956,11.55)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g></svg> months from January to December and the mean is called the monthly climatology.  Anomaly is calculated by subtracting the monthly climatology from data.  This anomaly calculation thus removes the climatic signals with the periods of 12, 6, 4, 3, 2.4, and 2 months which correspond to (12 months)/<svg style="vertical-align:-0.1638pt;width:8.6625004px;" id="M7" height="7.9499998" version="1.1" viewBox="0 0 8.6625004 7.9499998" width="8.6625004" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D45B" /></g></svg> with <svg style="vertical-align:-0.1638pt;width:36.237499px;" id="M8" height="11.125" version="1.1" viewBox="0 0 36.237499 11.125" width="36.237499" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,10.862)"><use xlink:href="#x1D45B" /></g><g transform="matrix(.017,-0,0,-.017,13.305,10.862)"><use xlink:href="#x3D" /></g><g transform="matrix(.017,-0,0,-.017,28.008,10.862)"><use xlink:href="#x31" /></g></svg>, 2, 3, 4, 5, and 6, respectively, whereas it retains other signals such as those with the periods of 11, 10, 9, 8, 7, and 5 months.  This paper suggests that one should be cautious when an anomaly field is used in research.  The conventional notion is that the monthly anomaly calculation removes the annual cycle.  However, here we show that the anomaly calculation removes all signals as long as the time length of the mean is an integer multiple of signals' period.

Chunzai Wang

Zhenya Song

Fangli Qiao

Shenfu Dong

What Signals Are Removed and Retained by Using an Anomaly Field in Climatic Research?

Two nonlinear regression methods, Bayesian neural network (BNN) and support vector regression (SVR), and linear regression (LR), were used to forecast the tropical Pacific sea surface temperature (SST) anomalies at lead times ranging from 3 to 15 months, using sea level pressure (SLP) and SST as predictors. Datasets for 1950–2005 and 1980–2005 were studied, with the latter period having the warm water volume (WWV) above the <svg style="vertical-align:-0.20473pt;width:32.787498px;" id="M1" height="13.1875" version="1.1" viewBox="0 0 32.787498 13.1875" width="32.787498" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,12.875)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g><g transform="matrix(.017,-0,0,-.017,8.222,12.875)"><path id="x30" d="M241 635q53 0 94 -28.5t63.5 -76t33.5 -102.5t11 -116q0 -58 -11 -112.5t-34 -103.5t-63.5 -78.5t-94.5 -29.5t-95 28t-64.5 75t-34.5 102.5t-11 118.5q0 58 11.5 112.5t34.5 103t64.5 78t95.5 29.5zM238 602q-32 0 -55.5 -25t-35.5 -68t-17.5 -91t-5.5 -105&#xA;q0 -76 10 -138.5t37 -107.5t69 -45q32 0 55.5 25t35.5 68.5t17.5 91.5t5.5 105t-5.5 105.5t-18 92t-36 68t-56.5 24.5z" /></g><g transform="matrix(.012,-0,0,-.012,16.375,4.712)"><path id="x2218" d="M326 255q0 -56 -41 -96t-99 -40t-99 40t-41 96t41 96t99 40t99 -40t41 -96zM274 255q0 38 -25.5 65t-62.5 27t-62.5 -27t-25.5 -65t25.5 -65t62.5 -27t62.5 27t25.5 65z" /></g><g transform="matrix(.017,-0,0,-.017,21.412,12.875)"><path id="x43" d="M614 175l29 -10q-33 -109 -57 -154q-121 -26 -184 -26q-90 0 -160.5 29t-112.5 77t-63.5 105.5t-21.5 119.5q0 157 108 253t277 96q36 0 71.5 -5t69 -13.5t36.5 -8.5q15 -102 20 -150l-29 -8q-20 79 -66.5 114t-128.5 35q-119 0 -187.5 -86t-68.5 -207&#xA;q0 -140 73.5 -227.5t188.5 -87.5q73 0 119.5 37.5t86.5 116.5z" /></g></svg> isotherm integrated across the equatorial Pacific available as an extra predictor. 

The forecasts indicated that the nonlinear structure is mainly present in the second PCA (principal component analysis) mode of the SST field. Overall, improvements in forecast skills by the nonlinear models over LR were modest. 
Although SVR has two structural advantages over neural network models, namely (a) no multiple minima in the optimization process and (b) an error norm robust to outliers in the data, it did not give better overall forecasts than BNN. 
Addition of WWV as an extra predictor generally increased the forecast skills slightly; however, the influence of WWV on SST anomalies in the tropical Pacific appears to be linear. 



Silvestre Aguilar-Martinez

William W. Hsieh

Forecasts of Tropical Pacific Sea Surface Temperatures by Neural Networks and Support Vector Regression

Spatio-temporal variations of chlorophylls and phycoerythrins, inferred by spectrofluorometric methods, were studied from April 2002 to June 2003 in the southwest lagoon and oceanic waters of New Caledonia. Trade winds blew 75% of the time and appeared as the main factor influencing surface Tchl<svg style="vertical-align:-0.1638pt;width:8.7250004px;" id="M1" height="7.9499998" version="1.1" viewBox="0 0 8.7250004 7.9499998" width="8.7250004" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><path id="x1D44E" d="M483 97q-42 -50 -88.5 -79.5t-68.5 -29.5q-37 0 -17 93l22 102h-2q-54 -79 -144 -149q-59 -46 -100 -46q-24 0 -43 29t-19 86q0 78 34.5 153t94.5 120q41 31 94 51.5t98 20.5q29 0 72 -9q26 -6 39 -6l2 -4q-30 -117 -67 -323q-8 -41 2 -41q16 0 79 58zM374 387&#xA;q-32 15 -73 15q-52 0 -83 -23q-48 -36 -78 -108.5t-30 -152.5q0 -33 8.5 -50.5t20.5 -17.5q31 0 107 79t99 132q15 40 29 126z" /></g></svg> (sum of monovinyl- and divinyl-chlorophyll <svg style="vertical-align:-0.1638pt;width:8.7250004px;" id="M2" height="7.9499998" version="1.1" viewBox="0 0 8.7250004 7.9499998" width="8.7250004" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D44E" /></g></svg>) variations in the ocean, near the barrier reef. Lagoon and oceanic waters differed in the composition of picoplanktonic cyanobacteria with a relative dominance of <i>Prochlorococcus</i> and high-phycourobilin <i>Synechococcus</i> in the ocean, and a relative dominance of high-phycoerythrobilin <i>Synechococcus</i> in the lagoon. Main pigment variations in the lagoon were associated with cyclone Erica in March 2003 and showed a 5-6 fold Tchl<svg style="vertical-align:-0.1638pt;width:8.7250004px;" id="M3" height="7.9499998" version="1.1" viewBox="0 0 8.7250004 7.9499998" width="8.7250004" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D44E" /></g></svg> increase around Nouméa. The cyclone stimulated mainly diatom growth as indicated by the high chlorophyll (<svg style="vertical-align:-3.27605pt;width:44.125px;" id="M4" height="12.5375" version="1.1" viewBox="0 0 44.125 12.5375" width="44.125" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,8.387)"><path id="x1D450" d="M383 397q0 -32 -35 -49q-12 -6 -23 8q-37 45 -84 45t-90 -71q-40 -65 -40 -167q0 -57 22 -86t59 -29q38 0 81.5 24.5t69.5 51.5l16 -21q-44 -53 -104 -84t-109 -31q-56 0 -89.5 41t-33.5 117q0 61 30 124t79 105q33 28 81 50.5t86 22.5q34 0 59 -15.5t25 -35.5z" /></g><g transform="matrix(.012,-0,0,-.012,6.962,12.475)"><path id="x31" d="M384 0h-275v27q67 5 81.5 18.5t14.5 68.5v385q0 38 -7.5 47.5t-40.5 10.5l-48 2v24q85 15 178 52v-521q0 -55 14.5 -68.5t82.5 -18.5v-27z" /></g><g transform="matrix(.017,-0,0,-.017,17.075,8.387)"><path id="x2B" d="M535 230h-212v-233h-58v233h-213v50h213v210h58v-210h212v-50z" /></g><g transform="matrix(.017,-0,0,-.017,30.827,8.387)"><use xlink:href="#x1D450" /></g><g transform="matrix(.012,-0,0,-.012,37.738,12.475)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g></svg>)/chlorophyll <svg style="vertical-align:-0.1638pt;width:8.7250004px;" id="M5" height="7.9499998" version="1.1" viewBox="0 0 8.7250004 7.9499998" width="8.7250004" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D44E" /></g></svg> ratio and by the lowest values for the other pigment ratios. The relative importance of divinyl-chlorophyll <svg style="vertical-align:-0.1638pt;width:8.7250004px;" id="M6" height="7.9499998" version="1.1" viewBox="0 0 8.7250004 7.9499998" width="8.7250004" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"><g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D44E" /></g></svg> concentration and fluorescence excitation spectra of phycoerythrins appeared as useful tools for characterizing lagoon-ocean exchanges.

J. Neveux

M. M. B. Ten&#xf3;rio

S. Jacquet

J.-P. Torr&#xe9;ton

P. Douillet

S. Ouillon

C. Dupouy

Chlorophylls and Phycoerythrins as Markers of Environmental Forcings Including Cyclone Erica Effect (March 2003) on Phytoplankton in the Southwest Lagoon of New Caledonia and Oceanic Adjacent Area

Sea surface height (SSH) and sea surface temperature (SST) in the North Indian Ocean are affected predominantly by the seasonally reversing monsoons and in turn feed back on monsoon variability. In this study, a set of data generated from a data-assimilative ocean model is used to examine coherent spatiotemporal modes of variability of winds and surface parameters using a frequency domain technique, Multiple Taper Method with Singular Value Decomposition (MTM-SVD). The analysis shows significant variability at annual and semiannual frequencies in these fields individually and jointly. The joint variability of winds and SSH is significant at interannual (2-3 years) timescale related to the ENSO mode—with a “/dipole/” like spatial pattern.  Joint variability with SST showed similar but somewhat weaker behavior. Winds appear to be the driver of variability in both SSH and SST at these frequency bands. This offers prospects for long-lead projections of the North Indian Ocean climate.

Thaned Rojsiraphisal

Balaji Rajagopalan

Lakshmi Kantha

The Use of MTM-SVD Technique to Explore the Joint Spatiotemporal Modes of Wind and Sea Surface Variability in the North Indian Ocean during 1993–2005

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International Journal of Oceanography