We investigated the impact of radiosonde data from the ice-free Arctic Ocean obtained by the Japanese R/V Mirai during a cruise in the fall of 2010 on the AFES-LETKF experimental ensemble reanalysis version 2 (ALERA2) data set. The reanalysis used radiosonde data over the ice-free region. Compared with observations, it captured Arctic cyclogenesis along the marginal ice zone, including a tropopause fold, very well.

We review the sea-level and energy budgets together from 1961, using recent and updated estimates of all terms. From 1972 to 2008, the observed sea-level rise (1.8 ± 0.2 mm yr−1 from tide gauges alone and 2.1 ± .2 mm yr−1 from a combination of tide gauges and altimeter observations) agrees well with the sum of contributions (1.8 ± 0.4 mm yr−1) in magnitude and with both having similar increases in the rate of rise during the period.

Absorbing aerosols affect global-mean precipitation primarily in two ways. They give rise to stronger shortwave atmospheric heating, which acts to suppress precipitation. Depending on the top-of-the-atmosphere radiative flux change, they can also warm up the surface with a tendency to increase precipitation.

The sensitivity of Amazon rainforests to dry?season droughts is still poorly understood, with reports of enhanced tree mortality and forest fires on one hand, and excessive forest greening on the other. Here, we report that the previous results of large?scale greening of the Amazon, obtained from an earlier version of satellite derived vegetation greenness data ? Collection 4 (C4)

A drought that happens once in a hundred years had little negative or positive effect on the Amazon rainforest according to this study led by Arindam Samanta from Boston University. Its results are different from 2007 IPCC report which stated that 40 percent of the Amazon rainforest was threatened by climate change.

Cooler North American temperatures in 2008 resulted from a strong natural effect, and the overall warming trend that has been observed since 1970 is likely to resume, according to this study. Using computer-generated models as well as observations, the team analyzed causes for climate variations in the recent decades. Special emphasis was given to the reasons for North American coolness in 2008.

Several recent studies have highlighted the possibility that the oceans and terrestrial ecosystems have started loosing part of their ability to sequester a large proportion of the anthropogenic CO2 emissions. This is an important claim, because so far only about 40% of those emissions have stayed in the atmosphere, which has prevented additional climate change.

The rate of sea level rise and its causes are topics of active debate. Here we use a delayed response statistical model to attribute the past 1000 years of sea level variability to various natural (volcanic and solar radiative) and anthropogenic (greenhouse gases and aerosols) forcings. We show that until 1800 the main drivers of sea level change are volcanic and solar radiative forcings.

Reliable forecasts of climate change in the immediate future are difficult, especially on regional scales, where natural climate variations may amplify or mitigate anthropogenic warming in ways that numerical models capture poorly.

Reliable medium range prediction of monsoon weather is crucial for disaster preparedness. Weather in tropics, controlled by fast growing convective instabilities is, however, intrinsically less predictable than that in extra?tropics.