FN Archimer Export Format PT J TI Mapping mesoscale variability of the azores current using TOPEX/POSEIDON and ERS 1 altimetry, together with hydrographic and Lagrangian measurements BT AF HERNANDEZ, fabrice LE TRAON, Pierre-Yves MORROW, R AS 1:;2:;3:; FF 1:;2:;3:; C1 GRP RECH GEODESIE SPATIALE,UNITE MIXTE RESH 39,F-31055 TOULOUSE,FRANCE. C2 GRP RECH GEODESIE SPATIALE,UNITE MIXTE RESH 39,F-31055 TOULOUSE,FRANCE. IF 2.68 TC 46 UR https://archimer.ifremer.fr/doc/00079/18978/16624.pdf LA English DT Article AB The SEMAPHORE mesoscale air/sea experiment was conducted in the Azores-Madeira region from July to November 1993. TOPEX/POSEIDON (T/P) and ERS 1 were flying simultaneously at that time. The main purposes of this paper are to evaluate the estimation of the oceanic mesoscale circulation from the two different sets of altimetric data (T/P and ERS 1) and to compare the results with in situ measurements provided by the SEMAPHORE hydrographic surveys and surface drifters (three expendable bathytermograph conductivity-temperature-depth surveys in a 500-km(2) box and a set of 47 Lagrangian surface drifters drogued at 150 m). Comparisons are carried out through the maps obtained by objective analysis from the four data sets. The mapping accuracy of T/P, ERS 1, T/P and ERS 1 combined, and in situ data is investigated, as well as the sensitivity of the mapping to the correlation functions used. There is a good qualitative agreement between altimetric maps and corresponding drifter and hydrographic maps for the three hydrographic surveys. Correlations are about 0.8, and the regression fit is about 0.6-0.7; the lower values are due to the smooth climatology used to reference the altimetric maps. The correlation for time differences is better, with regression lines not significantly different from 1, especially when ERS 1 and T/P are combined. T/P mapping is almost as good as ERS 1 mapping, which was rather unexpected since the ERS 1 space-time sampling is better suited for the mesoscale. This may reflect the fact that the signal mapped by the hydrography and drifters does not contain the high frequency/wavenumber components. T/P and ERS 1 combined provide better results, although the improvement is not as large as expected, probably for the same reason. PY 1995 PD DEC SO Journal Of Geophysical Research-oceans SN 0148-0227 PU Amer Geophysical Union VL 100 IS C12 UT A1995TL34100027 BP 24995 EP 25006 DI 10.1029/95JC02333 ID 18978 ER EF