63 citations · 162 across the 16 of their papers we have counts for
17 papers
The tipping effect of delayed interventions on the evolution of COVID-19 incidence
Kristoffer Rypdal
We combine infectious disease transmission and the non-pharmaceutical intervention (NPI) response to disease incidence into one closed model consisting of two coupled delay differe…
Intervention fatigue is the primary cause of strong secondary waves in the COVID-19 pandemic
Kristoffer Rypdal, Filippo Maria Bianchi, Martin Rypdal
As of November 2020, the number of COVID-19 cases is increasing rapidly in many countries. In Europe, the virus spread slowed considerably in the late spring due to strict lockdown…
A parsimonious description and cross-country analysis of COVID-19 epidemic curve
Kristoffer Rypdal, Martin Rypdal
In a given country, the cumulative death toll of the first wave of the COVID-19 epidemic follows a sigmoid curve as a function of time. In most cases, the curve is well described b…
Statistical significance of rising and oscillatory trends in global ocean and land temperature in the past 160 years
Lene Østvand, Kristoffer Rypdal, Martin Rypdal
Various interpretations of the notion of a trend in the context of global warming are discussed, contrasting the difference between viewing a trend as the deterministic response to…
Long-memory effects in linear-response models of Earth's temperature and implications for future global warming
Martin Rypdal, Kristoffer Rypdal
A linearized energy-balance model for global temperature is formulated, featuring a scale-free long-range memory (LRM) response and stochastic forcing representing the influence on…
ENSO dynamics: low-dimensional-chaotic or stochastic?
Tatjana Zivkovic, Kristoffer Rypdal
We apply a test for low-dimensional, deterministic dynamics to the Nino 3 time series for the El Nino Southern Oscillation (ENSO). The test is negative, indicating that the dynamic…