Cloud and ice in the planetary scale circulation and in climate

The roles of the cryosphere, and of cloud-radiative interactions are investigated. The effects clouds and ice have in the climate system are examined. The cloud radiation research attempts explain the modes of interaction (feedback) between raditive transfer, cloud formation, and atmospheric dynamics. The role of sea ice in weather and climate is also discussed. Models are used to describe the ice and atmospheric dynamics under study

Do labor market networks have an important spatial dimension?

We test for evidence of spatial, residence-based labor market networks. Turnover is lower for workers more connected to their neighbors generally and more connected to neighbors of the same race or ethnic group. Both results are consistent with networks producing better job matches, while the latter could also reflect preferences for working with neighbors of the same race or ethnicity. For earnings, we find a robust positive effect of the overall residence-based network measure, whereas we usually find a negative effect of the same-group measure, suggesting that the overall network measure reflects productivity-enhancing positive network effects, while the same-group measure may capture a non-wage amenity

Social Capital Determinants and Labor Market Networks

We explore the links between determinants of social capital and labor market networks at the neighborhood level. We harness rich data taken from multiple sources, including matched employer-employee data with which we measure the strength of labor market networks, data on neighborhood homogeneity that has previously been tied to social capital, and new data – not previously used in the study of social capital – on the number and location of non-profit sector establishments at the neighborhood level. We use a machine learning algorithm to identify the potential determinants of social capital that best predict neighborhood-level variation in labor market networks. We find evidence suggesting that smaller and less centralized schools, and schools with fewer poor students, foster social capital that builds local labor market networks, as does a larger Republican vote share. The presence of establishments in a number of non-profit-oriented industries are identified as predictive of strong labor market networks, likely because they either provide public goods or facilitate social contacts. These industries include, for example, churches and other religious institutions, fire and rescue services including volunteer fire departments, country clubs and golf courses, labor unions, chamber music groups, hobby clubs, and schools

Mismatch of N release from the permafrost and vegetative uptake opens pathways of increasing nitrous oxide emissions in the high Arctic

iogeochemical cycling in permafrost-affected ecosystems remains associated with large uncertainties, which could impact the Earth's greenhouse gas budget and future climate policies. In particular, increased nutrient availability following permafrost thaw could perturb the greenhouse gas exchange in these systems, an effect largely unexplored until now. Here, we enhance the terrestrial ecosystem model QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system), which simulates fully coupled carbon (C), nitrogen (N) and phosphorus (P) cycles in vegetation and soil, with processes relevant in high latitudes (e.g., soil freezing and snow dynamics). In combination with site-level and satellite-based observations, we use the model to investigate impacts of increased nutrient availability from permafrost thawing in comparison to other climate-induced effects and CO2 fertilization over 1960 to 2018 across the high Arctic. Our simulations show that enhanced availability of nutrients following permafrost thaw account for less than 15% of the total Gross primary productivity increase over the time period, despite simulated N limitation over the high Arctic scale. As an explanation for this weak fertilization effect, observational and model data indicate a mismatch between the timing of peak vegetative growth (week 26–27 of the year, corresponding to the beginning of July) and peak thaw depth (week 32–35, mid-to-late August), resulting in incomplete plant use of nutrients near the permafrost table. The resulting increasing N availability approaching the permafrost table enhances N loss pathways, which leads to rising nitrous oxide (N2O) emissions in our model. Site-level emission trends of 2 mg N m−2 year−1 on average over the historical time period could therefore predict an emerging increasing source of N2O emissions following future permafrost thaw in the high Arctic

Reexamining the barrier effect of the Tibetan Plateau on the South Asian summer monsoon

The Tibetan Plateau has been conventionally treated as an elevated heat source driving the Asian monsoon system, especially for the South Asian monsoon. Numerous model simulations with general circulation models (GCMs) support this hypothesis with the finding that the Asian monsoon system is weak or absent when all elevated topography is removed. A recent model simulation shows that the South Asian summer monsoon circulation is little affected with only the Himalayas (no-Tibetan Plateau) kept as a barrier, leading to a hypothesis of the barrier "blocking" mechanism of the Tibetan Plateau. In this paper, a new series of experiments are designed to reexamine this barrier effect. We find that with the barrier, the large-scale summer monsoon circulation over South Asia is simulated in general agreement with the full Tibetan Plateau, which is consistent with the previous finding. However, there remains significant differences in both wind and precipitation fields, suggesting a role for the full Tibetan Plateau as well. Moreover, the proposed barrier blocking mechanism is not found in our experiments. The energy of the low-level air and the convection are lower and weaker over the Indian subcontinent in the full Tibetan Plateau experiment than that in the no-Tibetan Plateau experiment or the barrier only experiment, which is in contrast to the barrier blocking hypothesis. Instead, there is a similar candle-like latent heating in the middle troposphere along the southern edge of the Tibetan Plateau in both the full Tibetan Plateau and the barrier experiments, whereas this "candle heating" disappears in the no-Tibetan Plateau experiment. We propose that this candle heating is the key to understanding the mechanisms of the Tibetan Plateau on the South Asian monsoon. Future studies are needed to check the source of the "candle heating" and its effect on the Asian monsoon