Recent  

We present a simple system to forecast the MJO. We are using atmospheric circulation as input to our system. We found a good skill forecast of the MJO amplitude within 40 days using this methodology. Comparing our results with ECMWF and machine learning forecasts confirmed the good skill of our system.

In this study, we benchmark the forecast skill of the NASA’s Goddard Earth Observing System subseasonal-to-seasonal (GEOS-S2S version 2) hydrometeorological forecasts in the High Mountain Asia (HMA) region. Hydrometeorological forecast skill is dependent on the forecast lead time, the memory of the variable within the physical system, and the validation dataset used. Overall, these results benchmark the GEOS-S2S system’s ability to forecast HMA hydrometeorology on the seasonal timescale.

The realistic representation of global teleconnections is an indispensable requirement for the reliable simulation of low-frequency climate variability and climate change. We present an application of the complex networks framework to quantify and evaluate large-scale interactions within and between ocean and atmosphere in 22 historical CMIP6 climate projections with respect to two century-long reanalyses.

The carbon cycling in terrestrial ecosystems is complex. In our analyses, we found both the global and the northern high latitude (NHL) ecosystems will continue to be carbon sinks in the next few decades under four global change scenarios but with large uncertainties. NHL ecosystems will experience faster climate warming but steadily contribute a small fraction to the global carbon sink. However, the relative uncertainty of NHL carbon sink is much larger than the global level values.

We study single and concurrent extreme heatwaves, droughts, maximum precipitation, and strong wind events. Globally, these extremes become more frequent and affect more land areas under future warming. Only a few years would go by without any extremes. Heatwaves-droughts are projected to increase the most in subtropical countries, whereas this is the case for high precipitation-wind in the tropics. More people will be exposed to these extreme events unless mitigation actions are urgently taken.

Climate change has been proven to be an indisputable fact and to be occurring at a faster rate in boreal forest areas. The results of this paper show that the boreal forest coverage has shown an increasing trend in the past three decades, and the area of broad-leaved forests has increased more rapidly than that of coniferous forests. In addition, temperature rather than precipitation is the main climate factor that is driving change.

We report on the ocean carbon sink and sources of uptake uncertainty from the latest version of the Coupled Model Intercomparison Project. We show that knowledge about historical regions of uptake will provide us information about future regions of uptake change and uncertainty. We break down the uncertainty to the sources and evaluate the dependence on location and integeration scale. Our results help us make useful suggestions for both modeling community and observational campaign planning.

Planting trees cools the climate by removing CO2 from the atmosphere, but may also cool or warm the climate by altering the albedo, roughness and evapotranspiration efficiency of the surface. To quantify these biogeophysical effects, we ran regional climate models over two idealized worlds, FOREST and GRASS, respectively representing maximum and minimum tree cover over North America and Europe. We find that these effects must be taken into account to successfully mitigate climate change.

We study the impact of a rapid melting of the ice sheets on monsoon systems during the 21^st century. The impact of a partial Antarctica melting is moderate. Conversely, Greenland melting slows down the oceanic Atlantic circulation, changes winds, temperature and pressure patterns, resulting in a southward shift of the tropical rain belt over Africa and America. The seasonality, duration and intensity of rainfall events are affected, with potential severe impacts on vulnerable population.