A5005376916- Climate variability and models
- Tropical and Extratropical Cyclones Research
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Oceanographic and Atmospheric Processes
- Flood Risk Assessment and Management
- Ocean Waves and Remote Sensing
- Marine and coastal ecosystems
- Meteorological Phenomena and Simulations
- Ionosphere and magnetosphere dynamics
- Methane Hydrates and Related Phenomena
- Solar and Space Plasma Dynamics
- Arctic and Antarctic ice dynamics
- Advanced Materials Characterization Techniques
- Ion-surface interactions and analysis
- Ocean Acidification Effects and Responses
- Urbanization and City Planning
- Geophysics and Gravity Measurements
- Coastal wetland ecosystem dynamics
- Geology and Paleoclimatology Research
- Electrodeposition and Electroless Coatings
- Hydrology and Drought Analysis
- Occupational Health and Safety Research
- Political Economy and Marxism
Climate Central
2022
Lewisham and Greenwich NHS Trust
2022
University Hospital Lewisham
2022
Goddard Institute for Space Studies
2009-2020
Faraday Technology (United States)
2018
Cornerstone Systems Northwest (United States)
2018
Portland State University
2018
Institute for Educational Leadership
2018
Georgetown University
2018
National Louis University
2018
We use a global climate model to compare the effectiveness of many forcing agents for producing change. find substantial range in “efficacy” different forcings, where efficacy is temperature response per unit relative CO 2 forcing. Anthropogenic CH 4 has ∼110%, which increases ∼145% when its indirect effects on stratospheric H O and tropospheric 3 are included, yielding an effective ∼0.8 W/m period 1750–2000 making largest anthropogenic other than . Black carbon (BC) aerosols from biomass...
Abstract A full description of the ModelE version Goddard Institute for Space Studies (GISS) atmospheric general circulation model (GCM) and results are presented present-day climate simulations (ca. 1979). This is a complete rewrite previous models incorporating numerous improvements in basic physics, stratospheric circulation, forcing fields. Notable changes include following: top now above stratopause, number vertical layers has increased, new cloud microphysical scheme used, vegetation...
Estimates of stratospheric age from observations long‐lived trace gases with increasing tropospheric concentrations invoke the implicit assumption that an air parcel has been transported intact tropopical tropopause. However, because rapid and irreversible mixing in stratosphere, a particular cannot be identified one left troposphere at some prior time. The contains mix range transit times, mean value over this is most appropriate definition age. measured tracer concentration also parcel,...
We review the relationship between tracer distributions and transport timescales in stratosphere discuss use of to evaluate constrain theories numerical models stratosphere. The “age spectrum,” distribution transit times since stratospheric air last made tropospheric contact, provides a way understand information tracers, how sensitive different tracers are various processes, combination rates. Trace gas observations can be used infer aspects age spectrum, most commonly “mean age,” but also...
Abstract. We investigate the issue of "dangerous human-made interference with climate" using simulations GISS modelE driven by measured or estimated forcings for 1880–2003 and extended to 2100 IPCC greenhouse gas scenarios as well "alternative" scenario Hansen Sato (2004). Identification "dangerous" effects is partly subjective, but we find evidence that added global warming more than 1°C above level in 2000 has may be highly disruptive. The alternative scenario, peak forcing ~1.5 W/m2 2100,...
We define the radiative forcings used in climate simulations with SI2000 version of Goddard Institute for Space Studies (GISS) global model. These include temporal variations well‐mixed greenhouse gases, stratospheric aerosols, solar irradiance, ozone, water vapor, and tropospheric aerosols. Our illustrations focus on period 1951–2050, but we make full data sets available those which have earlier data. illustrate response to these model specified sea surface temperature a simple Q ‐flux...
We evaluate transport characteristics of two‐ and three‐dimensional chemical models the stratosphere by comparing their simulations mean age stratospheric air propagation annually periodic oscillations in tracer mixing ratio at tropical tropopause into to inferences from situ satellite observations CO 2 , SF 6 water vapor. The models, participants recent NASA “Models Measurements II” study, display a wide range performance. Most propagate annual too rapidly vertical overattenuate signal....
The distribution of anthropogenic carbon (Cant) in the oceans is estimated using transit time (TTD) method applied to global measurements chlorofluorocarbon-12 (CFC12). Unlike most other inference methods, TTD does not assume a single ventilation and avoids large uncertainty incurred by attempts correct for natural background dissolved inorganic measurements. highest concentrations deepest penetration are found North Atlantic Southern Oceans. total inventory 1994 134 Pg-C. To evaluate...
Measurements of chemical tracers whose spatial gradients are primarily due to the time dependence sources and/or sinks often used define “tracer ages” in an effort diagnose transport. However, a major problem with interpreting these tracer ages is that different can yield ages, and at present, it not clear what aspects transport measured by tracers. We use concept distribution transit times compare timescales derived from tracers, including CFCs, tritium‐helium, radioactive By performing...
Transport in the atmosphere and ocean is result of complex action time-dependent often highly turbulent flow. A useful diagnostic that summarizes rate at which fluid elements are transported from some region to a point (or reverse) via multiplicity pathways mechanisms probability density function (pdf) transit times. The first moment this pdf, referred as "mean age," has become an important transport commonly used by observational community. This paper explores how probe flow with passive...
Submicron aerosols, as evidenced by the occurrence of polar mesospheric and noctilucent clouds, exist at heights from which mesosphere summer echoes (PMSE) are observed. We investigate role positively negatively charged aerosols in scattering processes proposed literature. These if substantially, can account for remarkably high radar reflectivity both VHF UHF raising electron Schmidt number through ambipolar effect. A component may be responsible enhanced scatter increasing incoherent power...
We present a statistical model of North Atlantic tropical cyclone tracks from genesis site through lysis. To propagate we use the means and variances latitudinal longitudinal displacements remaining anomalies as autoregressive. Coefficients are determined by averaging near-neighbour historical track data, with 'near' optimally using jackknife out-of-sample validation to maximize likelihood observations. The number cyclones in simulated year is sampled randomly record, sites spatial...
Recent studies of flood risk at New York Harbor (NYH) have shown disparate results for the 100-year storm tide, providing an uncertain foundation mitigation response after Hurricane Sandy. Here, we present a hazard assessment that improves confidence in our understanding region's present-day potential flooding, by separately including contribution tropical cyclones (TCs) and extratropical (ETCs), validating modeling study multiple stages against historical observations. The TC is based on...
Abstract The average speed of tropical cyclone (TC) translation has slowed since the mid 20th century. Here we report that North Atlantic (NA) TCs have become increasingly likely to “stall” near coast, spending many hours in confined regions. stalling is driven not only by slower translation, but also an increase abrupt changes direction. We compute residence-time distributions for coastal regions, and find tails these increased significantly. show over a region result more rain on region....
A general theory to describe and understand advective diffusive ocean transport is reported. It allows any passive tracer field with an atmospheric source be constructed by superposing sea surface contributions a generalized Green's function called the boundary propagator of equation. The has interpretation joint water-mass transit-time distribution from surface. thus includes classical oceanographic idea analysis extends it allow for transit times contains complete information about...
We present a technique to infer concentrations of anthropogenic carbon in the ocean from observable tracers and illustrate using synthetic data simple model. In contrast several recent studies, makes no assumptions about transport being dominated by bulk advection does not require separation small signal large variable natural cycle. Mixing is included naturally implicitly combination estimate distributions transit times surface interior points. The time‐varying waters propagated directly...
Abstract Hurricane Sandy's track crossed the New Jersey coastline at an angle closer to perpendicular than any previous hurricane in historic record, one of factors contributing record‐setting peak‐water levels parts and York. To estimate occurrence rate Sandy‐like tracks, we use a stochastic model built on historical data from entire North Atlantic generate large sample synthetic hurricanes. From this set calculate that under long‐term average climate conditions, intensity or greater...
Abstract The authors present a global climatology of tropical cyclones (TCs) that undergo extratropical transition (ET). ET is objectively defined based on TC’s trajectory through the cyclone phase space (CPS), which calculated using storm tracks from 1979–2017 best track data and geopotential height fields reanalysis datasets. Two reanalyses are used compared for this purpose, Japanese 55-yr Reanalysis ECMWF interim reanalysis. results to study seasonal geographical distributions storms...
During a campaign to study polar mesosphere summer echoes (PMSE) the European Incoherent Scatter (EISCAT) UHF and VHF radars Cornell University portable radar interferometer (CUPRI) were operated in Tromsö of 1988. Also, for first time EISCAT detected coherent from mesosphere. Their relation recorded simultaneously with CUPRI is studied, it shown that these 933‐MHz are same nature as echoes. Comparisons made PMSE electron density profile, measured radar. A narrow depletion seen data appears...