Preprints
Filtering by Subject: Climate
The joint influence of break and noise variance on the break detection capability in time series homogenization
Published: 2017-12-16
Subjects: Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Instrumental climate records of the last centuries suffer from multiple breaks due to relocations and changes in measurement techniques. These breaks are detected by relative homogenization algorithms using the difference time series between a candidate and a reference. Modern multiple changepoint methods use a decomposition approach where the segmentation explaining most variance defines the [...]
Non-crossing nonlinear regression quantiles by monotone composite quantile regression neural network, with application to rainfall extremes
Published: 2017-12-05
Subjects: Artificial Intelligence and Robotics, Climate, Computer Sciences, Earth Sciences, Hydrology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Statistical Models, Statistics and Probability
The goal of quantile regression is to estimate conditional quantiles for specified values of quantile probability using linear or nonlinear regression equations. These estimates are prone to "quantile crossing", where regression predictions for different quantile probabilities do not increase as probability increases. In the context of the environmental sciences, this could, for example, lead to [...]
Decreasing cloud cover drives the recent mass loss on the Greenland Ice Sheet
Published: 2017-11-14
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Environmental Sciences, Glaciology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The Greenland Ice Sheet (GrIS) has been losing mass at an accelerating rate since the mid-1990s. This has been due to both increased ice discharge into the ocean and melting at the surface, with the latter being the dominant contribution. This change in state has been attributed to rising temperatures and a decrease in surface albedo. We show, using satellite data and climate model output, that [...]
Increased ice loading in the Antarctic Peninsula since the 1850s and its effect on Glacial Isostatic Adjustment
Published: 2017-11-13
Subjects: Climate, Earth Sciences, Environmental Monitoring, Environmental Sciences, Geophysics and Seismology, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Other Earth Sciences, Other Environmental Sciences, Physical Sciences and Mathematics
Antarctic Peninsula (AP) ice core records indicate significant accumulation increase since 1855, and any resultant ice mass increase has the potential to contribute substantially to present-day Glacial Isostatic Adjustment (GIA). We derive empirical orthogonal functions from climate model output to infer typical spatial patterns of accumulation over the AP and, by combining with ice core records, [...]
Ratcheting up ambition in climate policy
Published: 2017-11-11
Subjects: Climate, Environmental Studies, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Social and Behavioral Sciences
The historic Paris Agreement aims to constrain the peak increase in global mean temperature to 1.5 °C, or at least well below 2 °C. Every country has committed to device their own “nationally determined contributions” towards this target. These contributions are only proscribed for the coming 10-15 years with a regular reassessment of them against the global target. Here we use a global [...]
Extreme UK Rainfall and Natural Climate Variability: Combining models and data
Published: 2017-11-11
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The return periods for extreme events are estimated from observational datasets. Often those datasets are relatively short in comparison to timescales of natural climate variability; potentially introducing a systematic bias into the extreme estimates. Here we combine observations with global climate models to show that this bias is statistically insignificant for the case of extreme UK-wide [...]
Weakening of nonlinear ENSO under global warming
Published: 2017-11-08
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
This is the pre-peer reviewed version of the following article: Kohyama, T., D. L. Hartmann, and D. S. Battisti (2018), Weakening of nonlinear ENSO under global warming, Geophys. Res. Lett., in press., which has been published in final form at https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079085 Abstract: The ENSO amplitude response to global warming is examined in two global [...]