|The authors have made substantial efforts in addressing the concerns raised by my earlier comments. To this reviewer, it is clear that the study does much more than “benefit(ing) the community by increasing the number of citations” (authors’ reply to previous Comment #8). Once the authors resolve several issues that arise from the previous revision (see below), I would be happy to recommend the publication of this study.|
1. Line 16-17 on Page 1: The tone of “alleged causes ... must be discarded” might need to be softer or balanced with a remark on caveats. As the authors mentioned in the last section, the findings of the study are based on specific ECMWF systems but may not necessarily apply to other models.
2. Line 1-5 on Page 19: It is confusing why the authors considered “circulation and rainfall associated with … warm SST biases (are) small”. Notably, the SST biases near 10N (Figs. 3 and 4c) can reach 0.5~1 K, and the warm biases appear to slightly lead or coincide with the manifestation of precipitation biases (e.g., Fig. 4c’s the double ITCZ feature at ~75 days after February 1st). Another issue that confuses me is how the spatial relation between “the strongest part of the northern ITCZ” (climatology) and the “warm SST biases” (bias) justify the assertion that the SST biases “only provides a small contribution to the overall bias development”. In addition, the impacts of SST anomalies/biases are often non-local. An example is the precipitation anomalies associated with the Atlantic meridional mode (Fig. 1 in Chiang and Vimont 2004).
- Chiang, J.C. and D.J. Vimont, 2004: Analogous Pacific and Atlantic Meridional Modes of Tropical Atmosphere–Ocean Variability. J. Climate, 17, 4143–4158, https://doi.org/10.1175/JCLI4953.1
3. Line 8-9 on Page 20: The decision of using the geopotential thickness between 700 and 1000 hPa as a proxy of boundary layer depth might need to be better justified. The 700-hPa level is likely well above the top of marine boundary layer, which is generally less than 2 km above the sea level (von Engeln and Teixeira 2013). Even with limited data, it might still be helpful to conduct some sensitivity tests (e.g., replacing 700 hPa with 850 hPa in calculations).
- von Engeln, A. and J. Teixeira, 2013: A Planetary Boundary Layer Height Climatology Derived from ECMWF Reanalysis Data. J. Climate, 26, 6575–6590, https://doi.org/10.1175/JCLI-D-12-00385.1