Contradictory Evidence on Wave Forcing of Tropical Upwelling in the Brewer-Dobson Circulation - A Suggested Resolution

ERA-40 data are analyzed to demonstrate that wave forcing at lower latitudes plays a crucial role in driving the tropical upwelling portion of the Brewer-Dobson circulation. It is shown that subtropical wave forcing is correlated with tropical upwelling on both intraseasonal and interannual time scales when transient waves are taken into account, and that tropical wave forcing exerts its influence on tropical upwelling via its body force on the zonal mean flow

Exploring the ENSO Modulation of the QBO Periods with GISS E2.2 Models

These datasets are used in Zhou et al. (2023): Exploring the ENSO Modulation of the QBO Periods with GISS E2.2 Models

Tropical Gravity Wave Momentum Fluxes and Latent Heating Distributions

Recent satellite determinations of global distributions of absolute gravity wave (GW) momentum fluxes in the lower stratosphere show maxima over the summer subtropical continents and little evidence of GW momentum fluxes associated with the intertropical convergence zone (ITCZ). This seems to be at odds with parameterizations forGWmomentum fluxes, where the source is a function of latent heating rates, which are largest in the region of the ITCZ in terms of monthly averages. The authors have examined global distributions of atmospheric latent heating, cloud-top-pressure altitudes, and lower-stratosphere absolute GW momentum fluxes and have found that monthly averages of the lower-stratosphere GW momentum fluxes more closely resemble the monthly mean cloud-top altitudes rather than the monthly mean rates of latent heating. These regions of highest cloud-top altitudes occur when rates of latent heating are largest on the time scale of cloud growth. This, plus previously published studies, suggests that convective sources for stratospheric GW momentum fluxes, being a function of the rate of latent heating, will require either a climate model to correctly model this rate of latent heating or some ad hoc adjustments to account for shortcomings in a climate model's land-sea differences in convective latent heating

Pto Mutants Differentially Activate Prf-Dependent, avrPto-Independent Resistance and Gene-for- Gene Resistance

Pto confers disease resistance to Pseudomonas syringae pv tomato carrying the cognate avrPto gene. Overexpression of Pto under the cauliflower mosaic virus 35S promoter activates spontaneous lesions and confers disease resistance in tomato (Lycopersicon esculentum) plants in the absence of avrPto. Here, we show that these AvrPto-independent defenses require a functional Prf gene. Several Pto-interacting (Pti) proteins are thought to play a role in Pto-mediated defense pathways. To test if interactions with Pti proteins are required for the AvrPto-independent defense responses by Pto overexpression, we isolated several Pto mutants that were unable to interact with one or more Pti proteins, but retained normal interaction with AvrPto. Overexpression of two mutants, Pto(G50S) and Pto(R150S), failed to activate AvrPto-independent defense responses or confer enhanced resistance to the virulent P. s. pv tomato. When introduced into plants carrying 35S::Pto, 35S::Pto(G50S) dominantly suppressed the AvrPto-independent resistance caused by former transgene. 35S::Pto(G50S) also blocked the induction of a number of defense genes by the wild-type 35S::Pto. However, 35S::Pto(G50S) and 35S::Pto(R150S) plants were completely resistant to P. s. pv tomato (avrPto), indicating a normal gene-for-gene resistance. Furthermore, 35S::Pto(G50S) plants exhibited normal induction of defense genes in recognition of avrPto. Thus, the AvrPto-independent defense activation and gene-for-gene resistance mediated by Pto are functionally separable

Exploring the effect of different tea varieties on the quality of Lu’an Guapian tea based on metabolomics and molecular sensory science

Lu’an Guapian (LAGP) tea is one of the most famous teas in China. However, research on its suitable processing varieties is still lacking. This study analyzed the quality of LAGP tea made from three different tea varieties, namely, ‘Anhui1’ (AH1), ‘Quntizhong’ (QTZ), and ‘Shuchazao’ (SCZ), using molecular sensory science and metabolomics techniques. The results showed that AH1 had a strong floral aroma and the strongest umami flavor, while QTZ had a distinct roasted aroma and a mellow taste. SCZ had a cooked corn-like aroma and the highest bitterness and astringency owing to the high tea polyphenol contents and low free amino acid contents. The study also identified 12 key aroma-active compounds, with trans-beta-ionone and 2-ethyl-3,5-dimethyl-pyrazine contributing the most to floral and roasted aromas, respectively. The results of this study provide a theoretical and practical basis for selecting and breeding high-quality varieties of LAGP tea and stabilizing its quality

New Gravity Wave Treatments for GISS Climate Models

Previous versions of GISS climate models have either used formulations of Rayleigh drag to represent unresolved gravity wave interactions with the model-resolved flow or have included a rather complicated treatment of unresolved gravity waves that, while being climate interactive, involved the specification of a relatively large number of parameters that were not well constrained by observations and also was computationally very expensive. Here, the authors introduce a relatively simple and computationally efficient specification of unresolved orographic and nonorographic gravity waves and their interaction with the resolved flow. Comparisons of the GISS model winds and temperatures with no gravity wave parameterization; with only orographic gravity wave parameterization; and with both orographic and nonorographic gravity wave parameterizations are shown to illustrate how the zonal mean winds and temperatures converge toward observations. The authors also show that the specifications of orographic and nonorographic gravity waves must be different in the Northern and Southern Hemispheres. Then results are presented where the nonorographic gravity wave sources are specified to represent sources from convection in the intertropical convergence zone and spontaneous emission from jet imbalances. Finally, a strategy to include these effects in a climate-dependent manner is suggested.Goddard Space Flight CenterUnited States. National Aeronautics and Space Administration (Atmospheric Composition: Modeling and Analysis Program

A Comparison between Gravity Wave Momentum Fluxes in Observations and Climate Models

International audienceFor the first time, a formal comparison is made between gravity wave momentum fluxes in models and those derived from observations. Although gravity waves occur over a wide range of spatial and temporal scales, the focus of this paper is on scales that are being parameterized in present climate models, sub-1000-km scales. Only observational methods that permit derivation of gravity wave momentum fluxes over large geographical areas are discussed, and these are from satellite temperature measurements, constant-density long-duration balloons, and high-vertical-resolution radiosonde data. The models discussed include two high-resolution models in which gravity waves are explicitly modeled, Kanto and the Community Atmosphere Model, version 5 (CAM5), and three climate models containing gravity wave parameterizations, MAECHAM5, Hadley Centre Global Environmental Model 3 (HadGEM3), and the Goddard Institute for Space Studies (GISS) model. Measurements generally show similar flux magnitudes as in models, except that the fluxes derived from satellite measurements fall off more rapidly with height. This is likely due to limitations on the observable range of wavelengths, although other factors may contribute. When one accounts for this more rapid fall off, the geographical distribution of the fluxes from observations and models compare reasonably well, except for certain features that depend on the specification of the nonorographic gravity wave source functions in the climate models. For instance, both the observed fluxes and those in the high-resolution models are very small at summer high latitudes, but this is not the case for some of the climate models. This comparison between gravity wave fluxes from climate models, high-resolution models, and fluxes derived from observations indicates that such efforts offer a promising path toward improving specifications of gravity wave sources in climate models