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Natalie P. Thomas, Michael G. Bosilovich, Allison B. Marquardt Collow, Randal D. Koster, Siegfried D. Schubert, Amin Dezfuli, and Sarith P. Mahanama

Climate Assessment (NCA; Wuebbles et al. 2017 ). (See Fig. A2 for further details on the process used to define heat-wave days and events.) c. Analysis method This analysis focuses on the North American warm season of June, July, and August (JJA) for 1980–2018. To analyze different variables that may be linked with daytime or nighttime heat waves, we utilize composite analysis. For this, daily averages of variables are averaged over all heat-wave days of a particular type, to determine dominant

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Rolf H. Reichle, Clara S. Draper, Q. Liu, Manuela Girotto, Sarith P. P. Mahanama, Randal D. Koster, and Gabrielle J. M. De Lannoy

.11, with strong improvements in many regions of the world ( Fig. 1d ), most notably in Africa. But there are also regions where the anomaly R skill of MERRA-2 is worse than that of MERRA, including portions of high-latitude North America, northern South America, West Africa, central Asia, and, naturally, Myanmar. MERRA-2 is also improved compared to MERRA-Land (average anomaly R difference of 0.08), with the strongest skill gains in the northern latitudes and Africa ( Fig. 1f ); this further

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Gloria L. Manney and Michaela I. Hegglin

equatorward rather than a poleward shift of the subtropical jet over northern Africa and Asia. However, a poleward shift is still seen over western North America and most of the Atlantic. The subtropical jet over the eastern Pacific ( Fig. S3 ) shifts toward two preferred positions. Greater rather than less (as in DJF) persistence of the high-latitude (poleward of about 60°N) jets is seen in some longitude regions, but Fig. S7 still indicates an equatorward shift of the polar jet in most regions. In SON

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Bin Guan, Duane E. Waliser, and F. Martin Ralph

Fig. 2c (the values are straight differences between Figs. 2a and 2b , not relative differences). In many regions outside the tropics, the increase is around 0.6%–0.9%, or 2–3 more AR days per year. Larger increases are seen in some tropical/subtropical regions, including southern North America into the Caribbean, central South America, northwest Africa, South/Southeast Asia, and Australia into French Polynesia. Most of these larger increases are located over land, suggesting an IVT threshold

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Rolf H. Reichle, Q. Liu, Randal D. Koster, Clara S. Draper, Sarith P. P. Mahanama, and Gary S. Partyka

suffers from excessive precipitation over topography ( Bosilovich et al. 2015 ). These errors are present in a relatively small surface area, but are sufficiently large to adversely impact the global RMS bias statistics. In winter, the M2AGCM precipitation ( Fig. 4c ) is too high over most of North America and Australia and much too high over large portions of South America, Africa, and the Maritime Continent, but much too low over central South America and central Africa, and too low over Europe and

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Kevin Hodges, Alison Cobb, and Pier Luigi Vidale

original wind speed data in knots is converted to wind speed in meters per second. The World Meteorological Organization (WMO) standard for reported tropical cyclone wind speed is maximum 10-min sustained winds at 10-m height over a smooth surface; however, this is rarely observed, so some discrepancy between agencies is apparent. Different agencies apply different wind-averaging periods, with the eastern Pacific, North Atlantic [Regional Specialized Meteorological Center (RSMC) Miami], and central

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Laura M. Hinkelman

reflected SW, but with lower amplitudes. For some land areas, the story is different. Despite the high reflection shown for central and northern Africa, the eastern portion of the Arabian Peninsula, the Amazon, and Antarctica, there is low-to-moderate cloud effect in these regions. There is also a region of higher cloud effect off the east coast of North America that does not appear in the reflected SW flux. Surface reflection, illustrated by the surface clear-sky upward SW flux in Fig. 4c , also

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Young-Kwon Lim, Robin M. Kovach, Steven Pawson, and Guillaume Vernieres

CP), compared to 1982/83 and 1997/98. The branch of sinking motion in the subtropical latitude (20°–25°N) is also quite well organized, stretching from the surface to the tropopause in 2015/16, whereas the EP El Niño of 1997/98 exhibits lower height of sinking motion. Better organized Hadley circulation over the CP in 2015/16 could reflect changes in jet strength and enhancement of the positive phase of the Pacific–North American (PNA) teleconnection ( Jayawardena et al. 2011 ; Li and Wettstein

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Clara S. Draper, Rolf H. Reichle, and Randal D. Koster

/Central America and the Sahel, although they do not agree as well over South Asia. Over South Asia Koster et al. (2006) does not locate a hot spot, while Miralles et al. (2012) identifies India as having the strongest coupling, and Fig. 3c suggests patchy regions of coverage spanning from Southeast Asia through the north of India. For reference, the corresponding maps for the austral summer (December–February) are shown in Fig. 1 of the supplemental material for R 2 anom (LH, SM) and Fig. 2 in the

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V. Buchard, C. A. Randles, A. M. da Silva, A. Darmenov, P. R. Colarco, R. Govindaraju, R. Ferrare, J. Hair, A. J. Beyersdorf, L. D. Ziemba, and H. Yu

. 2014 ; Nowottnick et al. 2015 ). Figure 2 compares the vertical structure of 532-nm attenuated backscatter from MERRA-2 and M2REPLAY sampled along the CALIOP track over regions of particular interest (e.g., the dust transport region from northern Africa to the North Atlantic, biomass burning regions of southern Africa and the Amazon, and over the continental United States; see inset map for region definitions). Seasonal medians are shown separately during the day and night for the period June

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