Tropical Atlantic variability modes (1979-2002). Part I: Time-evolving SST modes related to West African rainfall

May combine two claims.

The long-term downward trend in Sahelian summer rainfall is a unique feature in recent tropical fluctuations and has been associated with SST trends in the Atlantic and Indian Oceans.

“Such a long-term downward trend in Sahelian summer rainfall is a unique feature in recent tropical fluctuations, and it has been associated with SST trends in the Atlantic and Indian Oceans (Fol-land et al. 1986;Shinoda and Kawamura 1994;Bader and Latif 2003;Giannini et al. 2003;Lu and Delworth 2005).”

• cites Folland et al. 1986 sourceNot checked — no full text of the source
• cites Shinoda and Kawamura 1994 sourcePartly supported

  The Introduction describes a long-term decrease in Sahelian rainfall, and the Conclusions link the decline to Indian Ocean warming trends. The Conclusions instead associate the tropical Atlantic SST pattern mainly with shorter-term, interannual variation; our copy also does not establish that the Sahelian trend is unique among recent tropical fluctuations. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites Bader and Latif 2003 sourcePartly supported

  The Introduction (§1) documents a drying trend in Sahelian rainfall from the 1950s to the 1990s and associates rainfall variability with Atlantic and Indian Ocean SST anomalies. The Results (§3) identify Indian Ocean SSTs as particularly important for the West Sahel drying trend, while finding the Atlantic influence chiefly in coastal regions. Our copy does not establish that the rainfall trend was unique among recent tropical fluctuations. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

Warm tropical Atlantic SSTs could enhance the rainfall dipole.

“Paeth and Stuck (2004) have suggested that warm TA SSTs could enhance the rainfall dipole”

• cites Paeth and Stuck (2004) sourceSupported

May combine two claims.

For 1995 (1997), the time-longitude SLA plots at 5°S show the positive (negative) SLA signal at the southeast Atlantic propagating clearly westward as a Rossby wave.

“For 1995 (1997), the time-longitude SLA plots (Fig. 7) at 5°S show how the positive (negative) SLA signal at the southeast Atlantic is propagating clearly westward as a Rossby wave (Chelton and Schlax 1996;Polito and Cornillon 1997).”

• cites Chelton and Schlax 1996 sourceNot checked — no full text of the source
• cites Polito and Cornillon 1997 sourcePartly supported

  The Introduction (page unavailable) describes westward propagation of sea-surface-height anomalies at 27°N, and §4, Possible Forcing Mechanisms (page unavailable), characterizes the observed waves as baroclinic Rossby waves. Those passages support the general interpretation, but they do not document the specific positive 1995 and negative 1997 signals at 5°S in the southeast Atlantic. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

Significant increased Sahelian rainfall is simulated for the warm Mediterranean event of 2003, derived from enhanced evaporation in the Mediterranean Sea.

“Jung et al. (2006) have simulated significant increased Sahelian rainfall for the warm Mediterranean event of 2003, derived from enhanced evaporation in the Mediterranean Sea.”

• cites Jung et al. (2006) sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

The relation between Sahelian rainfall and the Atlantic SST meridional mode was more important before 1970, during the wet Sahel period.

“The relation between the Sahelian rainfall and the so-called Atlantic SST meridional mode (Chang et al. 1997) was pointed out to be more important before 1970, during the wet Sahel period (Janicot et al. 1996;Janicot et al. 2001)”

• cites Chang et al. 1997 sourceNot checked — no full text of the source
• cites Janicot et al. 1996 sourceSupported
• cites Janicot et al. 2001 sourceNot checked — no full text of the source

May combine two claims.

From JJAS to SOND, negative latent heat flux anomalies could be responsible for the damping at the south of the tongue, while radiative fluxes reduce the SST anomalies at the east.

“From JJAS to SOND, negative latent heat flux anomalies could be responsible for the damping at the south of the tongue, while radiative fluxes reduce the SST anomalies at the east, in agreement with Trzaska et al. (2007).”

• cites Trzaska et al. (2007) sourcePartly supported

  In “Air-sea interactions in the QB mode,” the paper says latent heat flux damps SST anomalies in the southeastern Atlantic, supporting the first mechanism. It says radiative feedback in the eastern basin is positive and increases SST-anomaly persistence, rather than reducing the anomalies there. The passages also do not establish the specific JJAS-to-SOND timing. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

Our results disagree with Latif and Grötzner (2000), Florenchie et al. (2003), and Wang (2006) with regard to the oceanic wave propagation's role in the origin of the equatorial and South Atlantic SST variability.

“Our results presented above disagree with Latif and Grötzner (2000), Florenchie et al. (2003), and Wang (2006) with regard to the oceanic wave propagation's role in the origin of the equatorial and South Atlantic SST variability.”

• cites Latif and Grötzner (2000) sourceNot checked — no full text of the source
• cites Florenchie et al. (2003) sourcePartly supported

  The Conclusion (§3, paragraph 10) says model evidence suggests equatorial thermocline perturbations propagate along the African coast as Kelvin waves and outcrop in the Benguela region. This supports a role for oceanic wave propagation in South Atlantic Benguela Niño SST anomalies, but not the broader claim about the origin of equatorial SST variability; the paper says the thermocline does not outcrop in the eastern equatorial Atlantic. (LLM, conf=0.83)

  Experimental — accuracy not yet measured
• cites Wang (2006) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

A seasonal correlation between autumn Guinean rainfall and the following summer Sahel rainfall has been found and evaluated by other authors, mainly as the result of soil moisture conditions persistence and developed vegetation interactions.

“a seasonal correlation between autumn Guinean rainfall and the following summer Sahel rainfall has been found and evaluated by other authors, mainly as the result of the soil moisture conditions persistence and the developed vegetation interactions (Philippon and Fontaine 2002;Fontaine et al. 2002;Douville et al. 2007).”

• cites Philippon and Fontaine 2002 sourcePartly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured
• cites Fontaine et al. 2002 sourceNot checked — no full text of the source
• cites Douville et al. 2007 sourceNot checked — no full text of the source

May combine two claims.

The 2003 Mediterranean warm event had anomalously high moisture advected from the Mediterranean by climatological Harmattan and Etesian winds, where enhanced moisture flux convergence leads to more precipitation.

“Jung et al. (2006) simulates the 2003 Mediterranean warm event, showing how the anomalously high moisture is advected from the Mediterranean by the climatological Harmattan and Etesian winds, where enhanced moisture flux convergence leads to more precipitation.”

• cites Jung et al. (2006) sourceSupported

May combine two claims.

The ocean is not the only factor explaining WA rainfall variability; land surface processes and the role of soil moisture and vegetation are also crucial factors.

“the ocean is not the only factor explaining the WA rainfall variability, and the interaction with land surface processes and the role played by soil moisture and vegetation are also crucial factors (Douville 2002;Philippon and Fontaine 2002).”

• cites Douville 2002 sourceNot checked — no full text of the source
• cites Philippon and Fontaine 2002 sourcePartly supported

  The Introduction identifies both sea-surface temperatures and land-surface properties as influences on West African rainfall. The Conclusion says rainfall variability could be partly controlled by land–atmosphere feedback involving soil moisture, while the Discussion says vegetation processes can contribute. The paper therefore supports the importance of land processes, but treats vegetation’s role as a possibility rather than establishing it as a crucial factor. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

May combine two claims.

Simultaneous with the westward upwelling (downwelling) Rossby wave traveling along 5°S, there is an upwelling (downwelling) Rossby wave traveling westward along 5°N latitude; the wind stress over 30°-20°W is also favoring (inhibiting) the Ekman pumping at both sides of the equator for 1995 (1997).

“Simultaneous with the westward upwelling (downwelling) Rossby wave traveling along 5°S (Figs.7a,b, left), there is an upwelling (downwelling) Rossby wave traveling westward along 5°N latitude (not shown); the wind stress over 30°-20°W is also favoring (inhibiting) the Ekman pumping at both sides of the equator for 1995 (1997).”

May combine two claims.

There is an enhancement of the clockwise circulation, together with a weakening of the subtropical Santa Helena high pressure system from the previous NDJF winter sequence.

“Noticeable is an enhancement of the clockwise circulation, together with a weakening of the subtropical Santa Helena high pressure system from the previous November-February (NDJF) winter sequence.”

May combine two claims.

The equatorial mode develops from FMAM to JJAS, starting with a maximum of anomalous SST over the Angola/Benguela upwelling region, with a second relative maximum around 20°S.

“Here, it can be seen that the EM develops from FMAM to JJAS, starting with a maximum of anomalous SST over the Angola/Benguela upwelling region, with a second relative maximum around 20°S.”

May combine two claims.

The whole equatorial mode starts to weaken, disappearing in SOND.

“Then, the whole mode starts to weaken, disappearing in SOND.”

May combine two claims.

From the previous winter months, anomalous southward wind stress locally changes the upwelling over the Benguela front, and thus the SST and the thermocline depth over the region.

“Figure 6a (and Figs.5a,b) shows how, from the previous winter months, anomalous southward wind stress locally changes the upwelling over the Benguela front, and thus the SST and the thermocline depth over the region (not shown).”

May combine two claims.

From JASO, positive Ekman pumping anomalies are located over the eastern part of the basin, because the southerly alongshore wind starts to be significant over 10°S, helping to damp the mode.

“From July to October (JASO), the positive Ekman pumping anomalies are located over the eastern part of the basin, because the southerly alongshore wind starts to be significant over 10°S, helping to damp the mode.”

May combine two claims.

The mean phase speed calculated for the westward propagation at 10°, 5°, and 2.5°S is −0.5 m s−1, and for the equatorial eastward propagation it is around 3 m s−1, corresponding approximately to the first baroclinic mode.

“The mean phase speed calculated for the westward propagation at 10°, 5°, and 2.5°S is Ϫ0.5 m s Ϫ1 , and for the equatorial eastward propagation it is around 3 m s Ϫ1 , corresponding approximately to the first baroclinic mode (Philander 1990;França et al. 2003).”

• cites Philander 1990Not checked — no full text of the source
• cites França et al. 2003 sourceNot checked — no full text of the source

May combine two claims.

At the beginning of July, the negative (positive) SLA signal appears in the western equatorial Atlantic and is reflected as an eastward Kelvin wave traveling up to September reaching the eastern equator, helping to damp the equatorial mode.

“At the beginning of July, this negative (positive) SLA signal appears in the western equatorial Atlantic and is reflected as an eastward Kelvin wave traveling up to September reaching the eastern equator (Figs.7c,d, right), and helping to damp the EM.”

May combine two claims.

Without standardization of rainfall anomalies, the rainfall anomalies of the coast of the Gulf of Guinea have higher amplitudes and appear as the leading mode.

“Without the standardization of the rainfall anomalies (as done in Giannini et al. 2003), the rainfall anomalies of the coast of the GG have higher amplitudes and appear as the leading mode.”

• cites Giannini et al. 2003 sourceNot checked — no full text of the source

May combine two claims.

Afterward, the equatorial mode shows strengthening and/or northward (westward) propagation of the coastal (equatorial) anomalies and a weakening of the anomalies in 20°S.

“Afterward, the mode shows a strengthening and/or northward (westward) propagation of the coastal (equatorial) anomalies and a weakening of the anomalies in 20°S.”

May combine two claims.

This eastern perturbation travels as far as 30°-20°W and does not propagate farther west, because an anomaly of the opposite sign appears.

“This eastern perturbation travels as far as 30°-20°W and does not propagate farther west (Figs.7a,b, left), because an anomaly of the opposite sign appears.”

May combine two claims.

The leading principal component of West African rainfall shows anomalous Sahelian rainfall (Sahelian mode) as the first mode, with more no-rain than wet periods during the whole sequence.

“The significant precipitation pattern of the leading principal component (PC) shows the anomalous Sahelian rainfall (Sahelian mode, see Fig. 2a) as the first mode, with more no-rain than wet periods during the whole sequence.”

May combine two claims.

The Sahelian and Guinean rainfall are separated in two different modes, not a dipole pattern.

“our results separate the Sahelian and the Guinean rainfall in two different modes.”

May combine two claims.

In MAMJ in the southwest Atlantic, the wind stress curl starts to be anomalously cyclonic, creating upward Ekman pumping and cooling the mixed layer at the west-central basin as the latent heat flux decreases.

“In March-June (MAMJ; see Fig. 6d) in the southwest Atlantic, the wind stress curl starts to be anomalously cyclonic, creating upward Ekman pumping and cooling the mixed layer at the westcentral basin as the latent heat flux decreases (Fig. 4c).”

May combine two claims.

The Guinean mode exhibits interannual and interdecadal variability, with more dry events over the coast of the Gulf of Guinea in the 1990s than in the 1980s.

“The pattern exhibits interannual and interdecadal variability, with more dry events over the coast of the GG in the 1990s than in the 1980s.”

May combine two claims.

During 1979-2002, most of the rainfall interannual variability is concentrated over the Sahel region, with the Guinean mode being the second EOF.

“from our results during 1979-2002, most of the rainfall interannual variability is concentrated over the Sahel region, with the Guinean mode being the second EOF.”

May combine two claims.

Both wind anomalies over the eastern South Atlantic and positive SST anomalies over the Benguela region are significant 2 months before negative SLP anomalies from SOND.

“However, both wind anomalies over the eastern South Atlantic and positive SST anomalies over the Benguela region (not shown) are significant 2 months before negative SLP anomalies from SOND.”

May combine two claims.

The SST signal over the Pacific differs for both modes: the Mediterranean mode is related to central equatorial Pacific SST, while the SNA mode is related to central-eastern equatorial Pacific SST.

“The SST signal over the Pacific is also different for both modes: the Mediterranean mode is related to central equatorial Pacific SST, while the SNA mode is related to the central-eastern equatorial Pacific.”

May combine two claims.

Different EMCA analyses show that the Mediterranean SST pattern has the major contribution on Sahel rainfall, while the direct influence of the SNA is not clear.

“Different EMCA analyses have shown that the Mediterranean SST pattern has the major contribution on Sahel rainfall, while the direct influence of the SNA is not clear.”

May combine two claims.

Global SST anomalies associated with the EM show SST anomalies decrease from the central to the east Pacific Ocean and increase at the western Pacific.

“SST anomalies decrease from the central to the east Pacific Ocean and increase at the western Pacific (Figs. 8a,d contour lines).”

May combine two claims.

There is a positive radiative flux anomaly over the Sahel region, which means that the Mediterranean influence is mainly nonconvective.

“There is a positive radiative flux anomaly over the Sahel region, which means that the Mediterranean influence is mainly nonconvective.”

May combine two claims.

Fig. 10b yields a North Atlantic pattern reminiscent of the previous winter tripole SST pattern and a tropical Pacific pattern resembling the decay phase of El Niño.

“Fig. 10b yields both a North Atlantic pattern, which is reminiscent of the previous winter tripole SST pattern (not shown), and a tropical Pacific pattern, which resembles the decay phase of El Niño (the remaining eastern anomaly accompanied by the opposite western surrounding one).”

May combine two claims.

The mode relates positive SST over the Mediterranean, maximum at the east, with increasing rainfall over the Sahel, particularly over the 10°-25°N, 5°-25°E region.

“The mode relates positive SST over the Mediterranean, maximum at the east, with increasing rainfall over the Sahel, in particular over the 10°-25°N, 5°-25°E region.”

May combine two claims.

For this period, Mediterranean Sea SST anomalies are the most important in driving Sahel anomalies, while central Pacific SST and eastern Indian Ocean SST explain less than 10% and 14%, respectively, of the SST-WA rainfall covariability.

“finding that, for this period, the Mediterranean Sea SST anomalies are the most important in driving Sahel anomalies, while the central Pacific SST and eastern Indian Ocean SST explains less than 10% and 14%, respectively, of the SST-WA rainfall covariability, and the SST evolution of those patterns is not very clear.”

May combine two claims.

The sum of the SST expansion coefficients of the SNA and Mediterranean Sea analyses separately is very similar to the SST expansion coefficient of the tropical Atlantic + Mediterranean mode, with a correlation coefficient of 0.82.

“the sum of the SST expansion coefficients of both analyses, considering the SNA and Mediterranean Sea separately (Fig. 9), is very similar to the SST expansion coefficient of the tropical Atlantic ϩ Mediterranean mode (Fig. 3, lower panel), with a correlation coefficient of 0.82 versus the low correlations in Table 1.”

May combine two claims.

The leading EMCA mode between Mediterranean SST anomalies and WA rainfall explains more than 33% of the covariance and is a very robust mode.

“The leading EMCA mode, obtained when considering just the Mediterranean SST anomalies (Fig. 9a), explains more than 33% of the covariance and is a very robust mode.”

May combine two claims.

Neither west-equatorial Atlantic SLA in winter nor anomalous winds in the west-central equatorial Atlantic have been found to force Benguela El Niños/equatorial mode via Kelvin waves.

“Our results show that neither west-equatorial Atlantic SLA in winter nor anomalous winds in the west-central equatorial Atlantic have been found to force Benguela El Niños/EM via Kelvin waves.”

May combine two claims.

The lead-lag correlation between the Mediterranean expansion coefficient and the Niño-3 index shows weak but significant scores and a 2-yr correlation cycle.

“the lead-lag correlation analysis between the Mediterranean expansion coefficient and the Niño-3 index shows, with weak but significant scores, a 2-yr correlation cycle that could give some insight into predictability issues (Fig. 10c).”

May combine two claims.

In JJAS, the second mode in Fig. 3 associates Sahelian anomalous rainfall with Mediterranean Sea SST anomalies persisting from FMAM and SNA SST anomalies damping from AMJJ.

“In JJAS, the second mode in Fig. 3 (lower panel) associates the Sahelian anomalous rainfall with Mediterranean Sea SST anomalies, persisting from FMAM, and SNA SST anomalies, damping from AMJJ.”

May combine two claims.

Using the CMAP rainfall dataset for 1979-2002, the first two summer WA rainfall EOF variability modes are Sahelian and Guinean rainfall patterns, which appear uncoupled.

“Using the CMAP rainfall dataset for the 1979-2002 period, the first two summer WA rainfall EOF variability modes have been determined as Sahelian and Guinean rainfall patterns, which appear as uncoupled ones.”

May combine two claims.

This pattern is more related to the third mode of variability when including the Mediterranean, with a correlation coefficient of 0.83 between the SST expansion coefficients.

“This pattern is itself more related to the third mode of variability when including the Mediterranean (not shown; the correlation coefficient between the both SST expansion coefficients is 0.83).”

May combine two claims.

The precipitation expansion coefficient correlation is statistically significant with both the first WA rainfall PC and the second EMCA rainfall expansion coefficient (0.96 and 0.90, respectively).

“The correlation of the precipitation expansion coefficient is statistically significant with both, with the first WA rainfall PC in Fig. 2a, and the second EMCA rainfall expansion coefficient in Fig. 3 (0.96 and 0.90, respectively; see Table 1).”

May combine two claims.

For SST expansion coefficients, the total analysis (tropical Atlantic + Mediterranean) is very similar to the TA analysis (r = 0.71), less significant for the Mediterranean Sea analysis (r = 0.49), and there is a very poor correlation between TA and the Mediterranean Sea analyses (r = 0.09).

“the result from the total analysis (tropical Atlantic ϩ Mediterranean) is very similar to the TA analysis (r ϭ 0.71), but is less significant for the Mediterranean Sea analysis (r ϭ 0.49), and there is a very poor correlation between TA and the Mediterranean Sea analyses (r ϭ 0.09).”

May combine two claims.

The regressed precipitation for the SNA mode shows positive anomalous rainfall over the eastern equatorial Pacific, the Western Hemisphere warm pool, and the Congo River basin region, and negative loadings over northeastern Brazil.

“The regressed precipitation for this SNA mode shows positive anomalous rainfall over the eastern equatorial Pacific, the Western Hemisphere warm pool (Wang 2002b), and the Congo River basin region, and negative loadings over northeastern Brazil.”

• cites Wang 2002bNot matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The monsoon flow is weak, and the Harmattan winds over the Sahel are strengthened.

“The monsoon flow is weak, and the Harmattan winds over the Sahel are strengthened.”

May combine two claims.

From JJAS to SOND, the Atlantic El Niño is damped, with a westward displacement of global tropical convection anomalies increasing West Asian precipitation and decreasing central to eastern Pacific precipitation (La Niña-like pattern).

“From JJAS to SOND, the Atlantic El Niño is being damped, with a westward displacement of the global tropical convection anomalies increasing the West Asian precipitation and decreasing the central to eastern Pacific precipitation (La Niña-like pattern).”

May combine two claims.

The SST mode starts at the Angola/Benguela region and is caused by alongshore wind anomalies.

“The SST mode starts at the Angola/Benguela region and is caused by alongshore wind anomalies.”

• Also stated in: § 1) EQUATORIAL ATLANTIC SST-GUINEAN RAINFALL MODE: AIR-SEA INTERACTIONS · hedged

  “Although the hypothesis needs to be checked using a model, we have found that the EM starts at the Angola/ Benguela upwelling region.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The Atlantic multidecadal oscillation can cause the observed multidecadal variations of Sahel summer rainfall.

“Zhang and Delworth (2006) have pointed out that the Atlantic multidecadal oscillation, which was in its negative phase in the 1980s-90s, can cause the observed multidecadal variations of Sahel summer rainfall”

• cites Zhang and Delworth (2006) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

The global picture suggests that Mediterranean SST anomalies are a fingerprint of large-scale forcing.

“Also, this global picture suggests that the Mediterranean SST anomalies are a fingerprint of large-scale forcing.”

May combine two claims.

The SST mode damps because of latent heat flux anomalies and Kelvin wave eastward propagation from an off-equatorial forcing.

“It then propagates westward via Rossby waves and damps because of latent heat flux anomalies and Kelvin wave eastward propagation from an off-equatorial forcing.”

Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing). May combine two claims.

The occurrence of dipole years is dominant during the wetter epoch, whereas nondipole years are particularly numerous in the dry Sahel period.

“Some of these studies have suggested that the occurrence of dipole years, which are most closely associated with TA SST, is dominant during the wetter epoch, whereas nondipole years are particularly numerous in the dry Sahel period (Ward 1998;Janicot et al. 2001)”

• cites Ward 1998 sourceNot checked — no full text of the source
• cites Janicot et al. 2001 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Two main West African rainfall types have been identified: dipole years and nondipole years.

“Historically, two main WA rainfall types have been identified: dipole years, in which anomalies of opposite signs appear north and south of 10°N, and nondipole years, with anomalies of the same sign in the whole region (Motha et al. 1980;Janicot 1992;Fontaine and Janicot 1996;Ward 1998).”

• cites Motha et al. 1980 sourceNot checked — no full text of the source
• cites Janicot 1992 sourceNot checked — no full text of the source
• cites Fontaine and Janicot 1996Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The Guinean rainfall pattern appears as the leading mode of covariability with tropical Atlantic SST, implying that an important part of the rainfall variability of the coast of the Gulf of Guinea can be explained by tropical Atlantic SST anomalies.

“It is important to mention that the Guinean rainfall pattern appears now as the leading mode of covariability with TA SST, implying that an important part of the rainfall variability of the coast of the GG can be explained by TA SST anomalies.”

May combine two claims.

Positive SLP anomalies cover the Amazon basin and the equatorial band, suggesting that subsequent weakening of the Santa Helena high could be forced by inversion of the local Hadley cell via an atmospheric bridge.

“At that moment, positive SLP anomalies cover the Amazon basin and the equatorial band (Figs.5a,b) suggests that subsequent weakening of the Santa Helena high could be forced by inversion of the local Hadley cell via an atmospheric bridge.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

ENSO acts by modifying the east-west divergent circulation, which modulates the vertical movements over West Africa, while the Pacific-Atlantic zonal atmospheric gradient, coupled to opposite SST anomalies over both oceanic basins, can enhance the West African rainfall response.

“ENSO seems to act by modifying the east-west divergent circulation, which modulates the vertical movements over WA, while the Pacific-Atlantic zonal atmospheric gradient, coupled to the opposite SST anomalies over both oceanic basins, can enhance the WA rainfall response (Janicot et al. 1998).”

• cites Janicot et al. 1998 sourceNot checked — no full text of the source

Classified as probably not a substantial claim. May combine two claims.

Such a feature could be responsible for the anomalous southeastward surface winds, and hence the SST warming.

“Such a feature could be responsible for the anomalous southeastward surface winds, and hence the SST warming.”

May combine two claims.

The Atlantic El Niño mode is characterized by a relaxation in the equatorial trade winds, which induces a redistribution of warm water in the equatorial belt and a weakening in the equatorial thermocline slope and heat content zonal gradient.

“The Atlantic El Niño mode is characterized by a relaxation in the equatorial trade winds, which induces a redistribution of warm water in the equatorial belt and a weakening in the equatorial thermoclime slope and also in the heat content zonal gradient (Carton et al. 1996;Vauclair et al. 2004).”

• cites Carton et al. 1996 sourceNot checked — no full text of the source
• cites Vauclair et al. 2004 sourceNot checked — no full text of the source

May combine two claims.

This SLA could be originated and/or reinforced by the Ekman pumping at this longitude, from the AMJJ season, and it is also propagating westward with the same phase speed, cancelling the positive (negative) SLA propagation farther west.

“This SLA could be originated and/or reinforced by the Ekman pumping at this longitude, from the AMJJ season, and it is also propagating westward with the same phase speed, cancelling the positive (negative) SLA propagation farther west.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Some discriminant analyses have shown perfect uncoupled rainfall variability modes between the Sahel and the coast of the Gulf of Guinea, associated with different global SST anomalies.

“However, some discriminant analyses have shown perfect uncoupled rainfall variability modes between the Sahel and the coast of the Gulf of Guinea (GG), associated with different global SST anomalies (Ward 1998;Giannini et al. 2003).”

• cites Ward 1998 sourceNot checked — no full text of the source
• cites Giannini et al. 2003 sourceNot checked — no full text of the source

May combine two claims.

The SLAs radiate and propagate westward as Rossby waves, and damp because of the latent heat flux anomalies at the South Atlantic and the Kelvin wave eastward propagation from an off-equatorial forcing.

“The SLAs radiate and propagate westward as Rossby waves, and damp because of the latent heat flux anomalies at the South Atlantic and the Kelvin wave eastward propagation from an off-equatorial forcing.”

May combine two claims.

Although both negative radiative and latent heat flux anomalies could be important in damping the SST in the equatorial mode, heat fluxes cannot explain the generation and persistence of the SST anomalies at the southeastern region.

“From the thermodynamics analysis of the EM, we conclude that, although both negative radiative and latent heat fluxes anomalies could be important in damping the SST in the EM, heat fluxes cannot explain the generation and persistence of the SST anomalies at the southeastern region.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Positive Mediterranean Sea SST anomalies are related to anomalous positive Sahel rainfall through evaporation and southward moisture advection that enhances low-level convergence over the Sahel.

“From AGCM simulations, Rowell (2003) has found positive Mediterranean Sea SST anomalies related to anomalous positive Sahel rainfall through evaporation and southward moisture advection that enhances low-level convergence over the Sahel.”

• cites Rowell (2003) sourceNot checked — no full text of the source

May combine two claims.

In cold years (dry years in the Gulf of Guinea region), the northward ITCZ movements can begin as early as February; warm years (wet years over the Gulf of Guinea) are characterized by a reduction of the southerly flow between April and June, followed by a rapid increase later in July.

“In cold years (dry years in the GG region), the northward ITCZ movements can begin as early as February.Conversely, the warm years (wet years over the GG) are characterized by a reduction of the southerly flow between April and June, followed by a rapid increase later in July (Fontaine et al. 2003).”

• cites Fontaine et al. 2003 sourceNot checked — no full text of the source

May combine two claims.

The reliability of the precipitation dataset and the use of EMCA technique as a tool for resolving time-evolving SST patterns in relation to anomalous WA rainfall have been evidenced.

“We have evidenced the reliability of the precipitation dataset as well as the use of EMCA technique as a tool for resolving time-evolving SST patterns in relation to the anomalous WA rainfall.”

May combine two claims.

The latent heat flux anomalies and the reversion of the wind anomalies also contribute to restore the normal conditions over the TA.

“The latent heat flux anomalies and the reversion of the wind anomalies also contribute to restore the normal conditions over the TA.”

May combine two claims.

Both TA and Mediterranean Sea SST anomalies covary with anomalous WA precipitation, but not necessarily in the same way.

“These results imply that both the TA and Mediterranean Sea SST anomalies covary with the anomalous WA precipitation, but not necessary in the same way.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The Pacific-Atlantic SST gradient drives atmospheric circulation across equatorial South America via the SLP gradient and influences tropical climate variability in a feedback way.

“Wang (2006) has discussed the importance of the Pacific-Atlantic SST gradient driving the atmospheric circulation across equatorial South America via the SLP gradient and influencing the tropical climate variability in a feedback way.”

• cites Wang (2006) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

At quasi-biennial time scales, a winter El Niño event leads an Atlantic El Niño the following summer with no significant simultaneous relationship.

“Latif and Grötzner (2000) showed how, at quasi-biennal time scales, a winter El Niño event leads an Atlantic El Niño the following summer with no significant simultaneous relationship.”

• cites Latif and Grötzner (2000) sourceNot checked — no full text of the source

May combine two claims.

The eastern anomalous SST creates a zonal gradient over the equatorial band, changing the thermocline slope.

“The eastern anomalous SST creates a zonal gradient over the equatorial band, changing the thermocline slope.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Additional heating over the Sahel could induce a stronger low-level inflow from the TA, which can explain the appearance of Mediterranean and SNA SST anomalies together associated with anomalous Sahel rainfall.

“Rowell (2003) also shows how the additional heating over the Sahel could induce a stronger low-level inflow from the TA, which can be an explanation for the appearance of the Mediterranean and SNA SST anomalies together associated with anomalous Sahel rainfall.”

• cites Rowell (2003) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The Mediterranean Sea influence on the WA monsoon regime has already been evidenced and studied with AGCM simulations.

“The Mediterranean Sea influence on the WA monsoon regime has already been evidenced (Rowell 2001) and studied with AGCM simulations (Rowell 2003).”

• cites Rowell 2001 sourceNot checked — no full text of the source
• cites Rowell 2003 sourceNot checked — no full text of the source

May combine two claims.

The different equatorial Pacific-Atlantic connection during the dry Sahel period implies a less active role of ENSO events on Sahelian rainfall anomalies, while the Pacific-Atlantic relationship has more influence on rainfall over the coast of the GG.

“This different equatorial Pacific-Atlantic connection during the dry Sahel period implies a less active role of the ENSO events on the Sahelian rainfall anomalies, while the Pacific-Atlantic relationship has more influence on the rainfall over the coast of the GG, because the Walker circulation is anomalous along the entire equatorial band.”

• AssumptionRests on an assumption: The 1979-2002 period is representative of the dry Sahel period.

May combine two claims.

A different sign SLA anomaly, induced by anomalous Ekman pumping at the west Atlantic, propagates eastward as a Kelvin oceanic wave, helping to damp the EM.

“A different sign SLA anomaly, induced by anomalous Ekman pumping at the west Atlantic, propagates eastward as Kelvin oceanic wave, helping to damp the EM.”

May combine two claims.

For the 1980s and 1990s, the EM is the most relevant mode affecting the GG region and there is no significant link with Sahelian rainfall.

“for the 1980s and 1990s the EM is the most relevant mode affecting the GG region and there is no significant link with the Sahelian rainfall.”

May combine two claims.

The result points out a different equatorial Pacific-Atlantic connection in the 1979-2002 period: the Atlantic El Niño can lead the Pacific La Niña.

“This is a very relevant result that points out a different equatorial Pacific-Atlantic connection in the 1979-2002 period: the Atlantic El Niño can lead the Pacific La Niña”

Probably not a substantial claim: may not pass S1 (asserted).

Some authors propose that SNA SST has a passive role or very limited effects on WA rainfall.

“there are some authors proposing that SNA SST has a passive role or very limited effects on WA rainfall (Ward 1998;Mo et al. 2001;Vizy and Cook 2001).”

• cites Ward 1998 sourceNot checked — no full text of the source
• cites Mo et al. 2001Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Vizy and Cook 2001Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.