Sources of plutonium in the atmosphere and stratosphere-troposphere mixing
نویسندگان
چکیده
Plutonium isotopes have primarily been injected to the stratosphere by the atmospheric nuclear weapon tests and the burn-up of the SNAP-9A satellite. Here we show by using published data that the stratospheric plutonium exponentially decreased with apparent residence time of 1.5 ± 0.5 years, and that the temporal variations of plutonium in surface air followed the stratospheric trends until the early 1980s. In the 2000s, plutonium and its isotope ratios in the atmosphere varied dynamically, and sporadic high concentrations of (239,240)Pu reported for the lower stratospheric and upper tropospheric aerosols may be due to environmental events such as the global dust outbreaks and biomass burning.
منابع مشابه
CO2 in the upper troposphere: Influence of stratosphere-troposphere exchange
[1] A two-dimensional transport model constrained to measured surface CO2 concentrations was used to simulate the spatial and temporal variation of CO2 in the atmosphere for the period from 1975 to 2004. We find that the amplitude, phase and shape of the CO2 seasonal cycle vary as a function of both altitude and latitude. Cross tropopause exchanges, especially the downward branch of the Brewer-...
متن کاملModeling Skylight and Aerial Perspective
Atmosphere Earth is enveloped by a vast amount of air called the atmosphere. It is relative thin compared to the size of the earth and fades away with increasing distance from the earth's surface. The earth's atmosphere is categorized into 4 layers troposphere, stratosphere, mesosphere and thermosphere. Troposphere where all the weather takes place and stratosphere, the two closest layers to ea...
متن کاملThe Extratropical Upper Troposphere and Lower Stratosphere
[1] The extratropical upper troposphere and lower stratosphere (Ex‐UTLS) is a transition region between the stratosphere and the troposphere. The Ex‐UTLS includes the tropopause, a strong static stability gradient and dynamic barrier to transport. The barrier is reflected in tracer profiles. This region exhibits complex dynamical, radiative, and chemical characteristics that place stringent spa...
متن کاملSeasonal cycle of COO, COO, and COO in the middle atmosphere: Implications for mesospheric dynamics and biogeochemical sources and sinks of CO2
[1] The isotopic anomaly of oxygen in atmospheric CO2 is caused by exchange reactions with isotopically anomalous O(D) in the middle atmosphere. In the stratosphere, the major source of O(D) is O3 photolysis; O3 is known to possess mass-independent isotopic composition, with dO3 dO3 100% relative to atmospheric O2. Higher in the mesosphere, Lyman a-driven photodissociation of O2 provides a more...
متن کاملSensitivity of tracer transports and stratospheric ozone to sea surface temperature patterns in the doubled CO2 climate
[1] Two sets of sea surface temperature/sea ice changes are used to test the sensitivity of tracer transport to the pattern of warming in the doubled CO2 climate. One set (2CO2WT) has greater tropical and high latitude sea surface temperature changes than the other (2CO2), although both fall within the range of plausible response. Simulations were done both with and without interactive ozone. R...
متن کامل