A5082078441- Ionosphere and magnetosphere dynamics
- Climate variability and models
- Atmospheric Ozone and Climate
- Meteorological Phenomena and Simulations
- Geophysics and Gravity Measurements
- GNSS positioning and interference
- Atmospheric and Environmental Gas Dynamics
- Ocean Waves and Remote Sensing
- Tropical and Extratropical Cyclones Research
- Solar and Space Plasma Dynamics
- Oceanographic and Atmospheric Processes
- Geophysics and Sensor Technology
- Calibration and Measurement Techniques
- Gas Dynamics and Kinetic Theory
- Aerospace Engineering and Energy Systems
- Fluid Dynamics and Turbulent Flows
- Atomic and Subatomic Physics Research
- Spacecraft and Cryogenic Technologies
University Corporation for Atmospheric Research
2017-2023
Colorado State University
2012-2017
Cooperative Institute for Research in Environmental Sciences
2017
University of Colorado Boulder
2017
NOAA Earth System Research Laboratory
2017
National Oceanic and Atmospheric Administration
2017
Abstract. Major, sudden midwinter stratospheric warmings (SSWs) are large and rapid temperature increases in the winter polar stratosphere associated with a complete reversal of climatological westerly winds (i.e., vortex). These extreme events can have substantial impacts on surface climate, including increased frequency cold air outbreaks over North America Eurasia anomalous warming Greenland eastern Canada. Here we present SSW Compendium (SSWC), new database that documents evolution...
Abstract Initial data from the Formosa Satellite‐7/Constellation Observing System for Meteorology Ionosphere and Climate (FORMOSAT‐7/COSMIC‐2, hereafter C2), a recently launched equatorial constellation of six satellites carrying advanced radio occultation receivers, exhibit high signal‐to‐noise ratio, precision, accuracy, ability to provide vertical resolution profiles bending angles refractivity, which contain information on temperature water vapor in challenging tropical atmosphere. After...
Abstract The amplitude of upward-propagating tropospherically forced planetary waves is known to be first-order importance in producing sudden stratospheric warmings (SSWs). This forcing observed undergo strong temporal fluctuations. Characteristics the resulting transient leading SSWs are studied reanalysis data and highly truncated simple models wave–mean flow interaction. It found both that preferentially generated by sufficiently long time scales (on order 1 week or longer). scale play a...
Abstract Each spring, the climatological westerly winds of Northern Hemisphere (NH) stratospheric polar vortex turn easterly as equator‐to‐pole temperature gradient relaxes. The timing this event is dictated both by annual return sunlight to pole and dynamical influences from troposphere. Here we consider predictability NH final warmings in multimodel hindcasts Subseasonal Seasonal project database. We evaluate how well prediction systems perform capturing warmings. compare early (which are...
Abstract The three-cornered hat (3CH) method, which was originally developed to assess the random errors of atomic clocks, is a means for estimating error variances three different datasets. Here we give an overview historical development 3CH and select other methods that use either two or We discuss similarities differences between these method. This study assesses sensitivity method factors limit its accuracy, including sample size, outliers, magnitudes datasets, biases, unknown...
We compare the random error statistics (uncertainties) of COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate, C1) COSMIC-2 (C2) radio occultation (RO) bending angles refractivities months August 2006 2021 over tropics subtropics using three-cornered hat method. The uncertainty profiles are similar two RO missions in troposphere. However, a higher percentage C2 reach close to surface moisture-rich tropics, an advantage signal-to-noise ratio (SNR) C2. uses signals...
Global navigation satellite system (GNSS) radio occultation (RO) receivers onboard the recently-launched COSMIC-2 (C2) constellation provide an unprecedented number of high vertical resolution moisture profiles throughout tropical and subtropical atmosphere. In this study, distribution variability water vapor was investigated using specific humidity retrievals from C2 observations compared to collocated ERA5 MERRA-2 reanalysis within 40°N 40°S September December 2019, which is prior...
Abstract A classic result of studying stratospheric wave–mean flow interactions presented by Holton and Mass is that, for constant incoming wave forcing (at a notional tropopause), vacillating response may ensue. Simple models, such as the Holton–Mass model, typically prescribe in terms geopotential perturbation, which not proxy upward activity flux. Here, authors reformulate model that flux prescribed. The contains positive feedback whereby decelerates mean flow, allowing enhanced...
Abstract We apply the three-cornered hat (3CH) method to estimate refractivity, bending angle, and specific humidity error variances for a number of data sets widely used in research and/or operations: radiosondes, radio occultation (COSMIC, COSMIC-2), NCEP global forecasts, nine reanalyses. use large combinations obtain insights into impact correlations among different that affect 3CH estimates. Error may be caused by actual errors, representativeness differences, or imperfect co-location...
Abstract. Major mid-winter sudden stratospheric warmings (SSWs) are large and rapid temperature increases in the wintertime polar stratosphere associated with a complete reversal of climatological westerly winds (i.e., vortex). These extreme events can have substantial impacts on surface climate, such as cold air outbreaks over North America Eurasia, or anomalous warming Greenland. Here we present SSW Compendium (SSWC), new database that documents evolution stratosphere, troposphere,...
Initial data from the Formosa Satellite-7/Constellation Observing System for Meteorology Ionosphere and Climate (FORMOSAT-7/COSMIC-2, hereafter C2), a recently launched Equatorial constellation of six satellites carrying advanced radio occultation receivers, exhibit high signal-to-noise ratio, precision, accuracy, ability to provide high-vertical-resolution information on temperature water vapor in challenging tropical atmosphere. After an initial calibration/validation phase, over 100,000...
We consider the accuracy and precision of COSMIC-2 (C2) radio occultation retrievals temperature, specific humidity, precipitable water (PW) in Hurricane Dorian ( 2019) larger-scale tropical subtropical environment by comparing them with ERA5, MERRA-2, JRA-55 reanalyses.Because its high signal-to-noise ratio, at least 70% C2 soundings penetrate to within 1 km surface over oceans, even extremely moist hurricane atmosphere.We compute biases standard deviations differences temperature humidity...
Abstract We compare two seemingly different methods of estimating random error statistics (uncertainties) observations, the three-cornered hat (3CH) method and Desroziers method, show several examples estimated uncertainties COSMIC-2 (C2) radio occultation (RO) observations. The yield similar results, attesting to validity both. small differences provide insight into sensitivity assumptions computational details. These estimates RO differ considerably from models used by operational weather...
Abstract. Observational estimates of Kelvin wave momentum fluxes in the tropical lower stratosphere remain challenging. Here we extend a method based on linear theory to estimate daily time series these from high-resolution radiosonde data. Daily are produced for sounding sites operated by US Department Energy (DOE) and recent Dynamics Madden–Julian Oscillation (DYNAMO) field campaign. Our flux found be robust different data sources processing quantitative agreement with prior studies....
Abstract Estimation of uncertainties (random error statistics) radio occultation (RO) observations is important for their effective assimilation in numerical weather prediction (NWP) models. Average can be estimated large samples RO and these statistics may used specifying the observation errors NWP data assimilation. However, individual vary, so using average uncertainty estimates will overestimate some underestimate those others, reducing overall effectiveness Several parameters associated...
Abstract. Observational estimates of Kelvin wave momentum fluxes in the tropical lower stratosphere remains challenging. Here we extend a method based on linear theory to estimate time series these from high-resolution radiosonde data. Testing sensitivity vertical resolution, our estimated are found be most sensitive resolution greater than 1 km, largely due overestimation wavelength. Estimates derived reanalyses and coarse-resolution satellite data notably larger. Daily produced for...
Figure S1.Time series of momentum fluxes from the Nauru ARM site.