Geophysical Fluid Dynamics Laboratory

About: Geophysical Fluid Dynamics Laboratory is a facility organization based out in Princeton, New Jersey, United States. It is known for research contribution in the topics: Climate model & Climate change. The organization has 525 authors who have published 2432 publications receiving 264545 citations. The organization is also known as: GFDL.

What Is the Predictability Limit of Midlatitude Weather

Abstract: Understanding the predictability limit of day-to-day weather phenomena such as midlatitude winter storms and summer monsoonal rainstorms is crucial to numerical weather prediction (NWP). Th...

Spiraling pathways of global deep waters to the surface of the Southern Ocean.

Abstract: Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution models. The analysis reveals that the northern-sourced deep waters enter the Antarctic Circumpolar Current via southward flow along the boundaries of the three ocean basins, before spiraling southeastward and upward through the Antarctic Circumpolar Current. Upwelling is greatly enhanced at five major topographic features, associated with vigorous mesoscale eddy activity. Deep water reaches the upper ocean predominantly south of the Antarctic Circumpolar Current, with a spatially nonuniform distribution. The timescale for half of the deep water to upwell from 30° S to the mixed layer is ~60–90 years. Deep waters of the Atlantic, Pacific and Indian Oceans upwell in the Southern Oceanbut the exact pathways are not fully characterized. Here the authors present a three dimensional view showing a spiralling southward path, with enhanced upwelling by eddy-transport at topographic hotspots.

TransCom model simulations of hourly atmospheric CO2: Experimental overview and diurnal cycle results for 2002

Abstract: [1] A forward atmospheric transport modeling experiment has been coordinated by the TransCom group to investigate synoptic and diurnal variations in CO2. Model simulations were run for biospheric, fossil, and air-sea exchange of CO2 and for SF6 and radon for 2000-2003. Twenty-five models or model variants participated in the comparison. Hourly concentration time series were submitted for 280 sites along with vertical profiles, fluxes, and meteorological variables at 100 sites. The submitted results have been analyzed for diurnal variations and are compared with observed CO2 in 2002. Mean summer diurnal cycles vary widely in amplitude across models. The choice of sampling location and model level account for part of the spread suggesting that representation errors in these types of models are potentially large. Despite the model spread, most models simulate the relative variation in diurnal amplitude between sites reasonably well. The modeled diurnal amplitude only shows a weak relationship with vertical resolution across models; differences in near-surface transport simulation appear to play a major role. Examples are also presented where there is evidence that the models show useful skill in simulating seasonal and synoptic changes in diurnal amplitude.

Tropospheric ozone trends at Mauna Loa Observatory tied to decadal climate variability

Abstract: Tropospheric ozone is a potent greenhouse gas, biological irritant and significant source of highly reactive hydroxyl radicals. Simulations with a chemistry climate model suggest that shifts in atmospheric circulation can account for the seasonally dependent trends in tropospheric ozone levels observed at Mauna Loa, Hawaii, over the past three decades.

Coupled chemistry climate model simulations of the solar cycle in ozone and temperature

Abstract: The 11-year solar cycles in ozone and temperature are examined using newsimulations of coupled chemistry climate models. The results show a secondary maximumin stratospheric tropical ozone, in agreement with satellite observations and in contrastwith most previously published simulations. The mean model response varies by upto about 2.5% in ozone and 0.8 K in temperature during a typical solar cycle, at the lowerend of the observed ranges of peak responses. Neither the upper atmospheric effectsof energetic particles nor the presence of the quasi biennial oscillation is necessaryto simulate the lower stratospheric response in the observed low latitude ozoneconcentration. Comparisons are also made between model simulations and observed totalcolumn ozone. As in previous studies, the model simulations agree well with observations.For those models which cover the full temporal range 1960–2005, the ozone solarsignal below 50 hPa changes substantially from the first two solar cycles to the last twosolar cycles. Further investigation suggests that this difference is due to an aliasingbetween the sea surface temperatures and the solar cycle during the first part of the period.The relationship between these results and the overall structure in the tropical solarozone response is discussed. Further understanding of solar processes requiresimprovement in the observations of the vertically varying and column integrated ozone.