scholarly journals HOAPS and ERA-Interim precipitation over sea: Validation against shipboard in-situ measurements

2016 ◽  
Author(s):  
Karl Bumke ◽  
Gert König-Langlo ◽  
Julian Kinzel ◽  
Marc Schröder
Keyword(s):  
Reanalysis Data ◽  
Data Sets ◽  
Weather Forecasts ◽  
Rain Gauges ◽  
Medium Range ◽  
Temporal And Spatial ◽  
The Tropics ◽  
Along Track ◽  
Spatial Threshold

Abstract. The satellite derived HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data) and ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim reanalysis data sets have been validated against in-situ precipitation measurements from ship rain gauges and optical disdrometers over the open-ocean by applying a statistical analysis for binary forecasts. For this purpose collocated pairs of data were merged within a certain temporal and spatial threshold into single events, according to the satellites' overpass, the observation and the forecast times. HOAPS detects the frequency of precipitation well, while ERA-Interim strongly overestimates it, especially in the tropics and subtropics. Although precipitation rates are difficult to compare because along-track point measurements are collocated with areal estimates and the numbers of available data are limited, we find that HOAPS underestimates precipitation rates, while ERA-Interim's Atlantic-wide average precipitation rate is close to measurements. However, regionally averaged over latitudinal belts, there are deviations between the observed mean precipitation rates and ERA-Interim. The most obvious ERA-Interim feature is an overestimation of precipitation in the area of the intertropical convergence zone and the southern sub-tropics over the Atlantic Ocean. For a limited number of snow measurements by optical disdrometers it can be concluded that both HOAPS and ERA-Interim are suitable to detect the occurrence of solid precipitation.

scholarly journals HOAPS and ERA-Interim precipitation over the sea: validation against shipboard in situ measurements

2016 ◽  
Vol 9 (5) ◽  
pp. 2409-2423 ◽  
Author(s):  
Karl Bumke ◽  
Gert König-Langlo ◽  
Julian Kinzel ◽  
Marc Schröder
Keyword(s):  
Reanalysis Data ◽  
Data Sets ◽  
Weather Forecasts ◽  
Rain Gauges ◽  
Medium Range ◽  
Temporal And Spatial ◽  
The Tropics ◽  
Along Track ◽  
Spatial Threshold

Abstract. The satellite-derived HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) and ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim reanalysis data sets have been validated against in situ precipitation measurements from ship rain gauges and optical disdrometers over the open ocean by applying a statistical analysis for binary estimates. For this purpose collocated pairs of data were merged within a certain temporal and spatial threshold into single events, according to the satellites' overpass, the observation and the ERA-Interim times. HOAPS detects the frequency of precipitation well, while ERA-Interim strongly overestimates it, especially in the tropics and subtropics. Although precipitation rates are difficult to compare because along-track point measurements are collocated with areal estimates and the number of available data are limited, we find that HOAPS underestimates precipitation rates, while ERA-Interim's Atlantic-wide average precipitation rate is close to measurements. However, when regionally averaged over latitudinal belts, deviations between the observed mean precipitation rates and ERA-Interim exist. The most obvious ERA-Interim feature is an overestimation of precipitation in the area of the intertropical convergence zone and the southern subtropics over the Atlantic Ocean. For a limited number of snow measurements by optical disdrometers, it can be concluded that both HOAPS and ERA-Interim are suitable for detecting the occurrence of solid precipitation.

Impact of planetary waves on infrasound propagation uncertainties

2021 ◽  
Author(s):  
Elisabeth Blanc ◽  
Patrick Hupe ◽  
Bernd Kaifler ◽  
Natalie Kaifler ◽  
Alexis Le Pichon ◽  
...  
Keyword(s):  
Wave Activity ◽  
Atmospheric Dynamics ◽  
Planetary Waves ◽  
Data Sets ◽  
Atmospheric Models ◽  
Period Range ◽  
Weather Forecasts ◽  
Atmospheric Disturbances ◽  
Medium Range ◽  
Model Improvement

<p>The uncertainties in the infrasound technology arise from the middle atmospheric disturbances, which are partly underrepresented in the atmospheric models such as in the European Centre for Medium-Range Weather Forecasts (ECMWF) products used for infrasound propagation simulations. In the framework of the ARISE (Atmospheric dynamics Research InfraStructure in Europe) project, multi-instrument observations are performed to provide new data sets for model improvement and future assimilations. In an unexpected way, new observations using the autonomous CORAL lidar showed significant differences between ECMWF analysis fields and observations in Argentina in the period range between 0.1 and 10 days. The model underestimates the wave activity, especially in the summer. During the same season, the infrasound bulletins of the IS02 station in Argentina indicate the presence of two prevailing directions of the detections, which are not reflected by the simulations. Observations at the Haute Provence Observatory (OHP) are used for comparison in different geophysical conditions. The origin of the observed anomalies are discussed in term of planetary waves effect on the infrasound propagation.</p>

Evaluation of Global Forecast System (GFS) Medium-Range Precipitation Forecasts in the Nile River Basin

2021 ◽  
Author(s):  
Haowen Yue ◽  
Mekonnen Gebremichael ◽  
Vahid Nourani
Keyword(s):  
Temporal Dynamics ◽  
Disease Outbreaks ◽  
Rain Gauge ◽  
Global Forecast System ◽  
Forecast System ◽  
Forecast Performance ◽  
Weather Forecasts ◽  
Rain Gauges ◽  
Basin Scale ◽  
Medium Range

Abstract Reliable weather forecasts are valuable in a number of applications, such as, agriculture, hydropower, and weather-related disease outbreaks. Global weather forecasts are widely used, but detailed evaluation over specific regions is paramount for users and operational centers to enhance the usability of forecasts and improve their accuracy. This study presents evaluation of the Global Forecast System (GFS) medium-range (1 day – 15 day) precipitation forecasts in the nine sub-basins of the Nile basin using NASA’s Integrated Multi-satellitE Retrievals (IMERG) “Final Run” satellite-gauge merged rainfall observations. The GFS products are available at a temporal resolution of 3-6 hours, spatial resolution of 0.25°, and its version-15 products are available since 12 June 2019. GFS forecasts are evaluated at a temporal scale of 1-15 days, spatial scale of 0.25° to all the way to the sub-basin scale, and for a period of one year (15 June 2019 – 15 June 2020). The results show that performance of the 1-day lead daily basin-averaged GFS forecast performance, as measured through the modified Kling-Gupta Efficiency (KGE), is poor (0 < KGE < 0.5) for most of the sub-basins. The factors contributing to the low performance are: (1) large overestimation bias in watersheds located in wet climate regimes in the northern hemispheres (Millennium watershed, Upper Atbara & Setit watershed, and Khashm El Gibra watershed), and (2) lower ability in capturing the temporal dynamics of watershed-averaged rainfall that have smaller watershed areas (Roseires at 14,110 sq. km and Sennar at 13,895 sq. km). GFS has better bias for watersheds located in the dry parts of the northern hemisphere or wet parts of the southern hemisphere, and better ability in capturing the temporal dynamics of watershed-average rainfall for large watershed areas. IMERG Early has better bias than GFS forecast for the Millennium watershed but still comparable and worse bias for the Upper Atbara & Setit, and Khashm El Gibra watersheds. The variation in the performance of the IMERG Early could be partly explained by the number of rain gauges used in the reference IMERG Final product, as 16 rain gauges were used for the Millennium watershed but only one rain gauge over each Upper Atbara & Setit, and Khashm El Gibra watershed. A simple climatological bias-correction of IMERG Early reduces in the bias in IMERG Early over most watersheds, but not all watersheds. We recommend exploring methods to increase the performance of GFS forecasts, including post-processing techniques through the use of both near-real-time and research-version satellite rainfall products.

scholarly journals Estimating the Spatial Distribution of Precipitation in Iceland Using a Linear Model of Orographic Precipitation

2007 ◽  
Vol 8 (6) ◽  
pp. 1285-1306 ◽  
Author(s):  
Philippe Crochet ◽  
Tómas Jóhannesson ◽  
Trausti Jónsson ◽  
Oddur Sigurðsson ◽  
Helgi Björnsson ◽  
...  
Keyword(s):  
Linear Model ◽  
Reanalysis Data ◽  
Orographic Precipitation ◽  
Mountainous Terrain ◽  
Physical Processes ◽  
Weather Forecasts ◽  
Simulated Precipitation ◽  
Medium Range ◽  
Condensed Water ◽  
Good Agreement

Abstract A linear model of orographic precipitation that includes airflow dynamics, condensed water advection, and downslope evaporation is adapted for Iceland. The model is driven using coarse-resolution 40-yr reanalysis data from the European Centre for Medium-Range Weather Forecasts (ERA-40) over the period 1958–2002. The simulated precipitation is in good agreement with precipitation observations accumulated over various time scales, both in terms of magnitude and distribution. The results suggest that the model captures the main physical processes governing orographic generation of precipitation in the mountains of Iceland. The approach presented in this paper offers a credible method to obtain a detailed estimate of the distribution of precipitation in mountainous terrain for various conditions involving orographic generation of precipitation. It appears to be of great practical value to the hydrologists, glaciologists, meteorologists, and climatologists.

scholarly journals Validation of the Aura High Resolution Dynamics Limb Sounder geopotential heights

2014 ◽  
Vol 7 (2) ◽  
pp. 1001-1025
Author(s):  
L. L. Smith ◽  
J. C. Gille
Keyword(s):  
High Resolution ◽  
System Model ◽  
Weather Forecasts ◽  
Atmospheric Research ◽  
Earth Observing System ◽  
Medium Range ◽  
High Bias ◽  
Environmental Prediction ◽  
The Tropics ◽  
Data Screening

Abstract. Global satellite observations from the EOS Aura spacecraft's High Resolution Dynamics Limb Sounder (HIRDLS) of temperature and geopotential height (GPH) are discussed. The accuracy, resolution and precision of the HIRDLS version 7 algorithms are assessed and data screening recommendations are made. Comparisons with GPH from observations, reanalyses and models including European Center for Medium-Range Weather Forecasts Interim Reanalysis (ERA-Interim), National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis, Goddard Earth Observing System Model (GEOS) version 5, and EOS Aura Microwave Limb Sounder (MLS) illustrate the HIRDLS GPH have a precision ranging from 2 m to 30 m and an accuracy of ±100 m. Comparisons indicate HIRDLS GPH may have a slight low bias in the tropics and a slight high bias at high latitudes. Geostrophic winds computed with HIRDLS GPH qualitatively agree with winds from other data sources including ERA-Interim, NCEP and GEOS-5.

scholarly journals A comparison of Loon balloon observations and stratospheric reanalysis products

2017 ◽  
Vol 17 (2) ◽  
pp. 855-866 ◽  
Author(s):  
Leon S. Friedrich ◽  
Adrian J. McDonald ◽  
Gregory E. Bodeker ◽  
Kathy E. Cooper ◽  
Jared Lewis ◽  
...  
Keyword(s):  
Reanalysis Data ◽  
Location Information ◽  
Data Sets ◽  
Wind Fields ◽  
Weather Forecasts ◽  
Wind Speeds ◽  
Zonal Winds ◽  
Long Duration ◽  
Environmental Prediction ◽  
Modern Era

Abstract. Location information from long-duration super-pressure balloons flying in the Southern Hemisphere lower stratosphere during 2014 as part of X Project Loon are used to assess the quality of a number of different reanalyses including National Centers for Environmental Prediction Climate Forecast System version 2 (NCEP-CFSv2), European Centre for Medium-Range Weather Forecasts (ERA-Interim), NASA Modern Era Retrospective-Analysis for Research and Applications (MERRA), and the recently released MERRA version 2. Balloon GPS location information is used to derive wind speeds which are then compared with values from the reanalyses interpolated to the balloon times and locations. All reanalysis data sets accurately describe the winds, with biases in zonal winds of less than 0.37 m s−1 and meridional biases of less than 0.08 m s−1. The standard deviation on the differences between Loon and reanalyses zonal winds is latitude-dependent, ranging between 2.5 and 3.5 m s−1, increasing equatorward. Comparisons between Loon trajectories and those calculated by applying a trajectory model to reanalysis wind fields show that MERRA-2 wind fields result in the most accurate simulated trajectories with a mean 5-day balloon–reanalysis trajectory separation of 621 km and median separation of 324 km showing significant improvements over MERRA version 1 and slightly outperforming ERA-Interim. The latitudinal structure of the trajectory statistics for all reanalyses displays marginally lower mean separations between 15 and 35° S than between 35 and 55° S, despite standard deviations in the wind differences increasing toward the equator. This is shown to be related to the distance travelled by the balloon playing a role in the separation statistics.

scholarly journals Validation of the Aura High Resolution Dynamics Limb Sounder geopotential heights

2014 ◽  
Vol 7 (8) ◽  
pp. 2775-2785 ◽  
Author(s):  
L. L. Smith ◽  
J. C. Gille
Keyword(s):  
High Resolution ◽  
High Latitudes ◽  
Weather Forecasts ◽  
Atmospheric Research ◽  
Earth Observing System ◽  
Medium Range ◽  
High Bias ◽  
Environmental Prediction ◽  
The Tropics ◽  
Data Screening

Abstract. The geopotential height (GPH) product created from global observations by the High Resolution Dynamics Limb Sounder (HIRDLS) instrument on NASA's Earth Observing System (EOS) Aura spacecraft is discussed. The accuracy, resolution and precision of the HIRDLS version 7 algorithms are assessed and data screening recommendations are made. Comparisons with GPH from observations, reanalyses and models including European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-Interim), and National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis illustrate the HIRDLS GPHs have a precision ranging from 2 to 30 m and an accuracy of ±100 m up to 1 hPa. Comparisons indicate HIRDLS GPH may have a slight low bias in the tropics and a slight high bias at high latitudes. Geostrophic winds computed with HIRDLS GPH qualitatively agree with winds from other data sources including ERA-Interim.

scholarly journals Validation of HOAPS Rain Retrievals against OceanRAIN In-Situ Measurements over the Atlantic Ocean

Atmosphere ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 15
Author(s):  
Karl Bumke ◽  
Robin Pilch Kedzierski ◽  
Marc Schröder ◽  
Christian Klepp ◽  
Karsten Fennig
Keyword(s):  
Phase Precipitation ◽  
Perfect Agreement ◽  
Precipitation Measurement ◽  
Precipitation Estimates ◽  
The Mean ◽  
Temporal And Spatial ◽  
High Precipitation ◽  
Observation Times ◽  
Spatial Threshold

The satellite-derived HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) precipitation estimates have been validated against in-situ precipitation measurements from optical disdrometers, available from OceanRAIN (Ocean Rainfall And Ice-phase precipitation measurement Network) over the open-ocean by applying a statistical analysis for binary estimates. In addition to using directly collocated pairs of data, collocated data were merged within a certain temporal and spatial threshold into single events, according to the observation times. Although binary statistics do not show perfect agreement, simulations of areal estimates from the observations themselves indicate a reasonable performance of HOAPS to detect rain. However, there are deficits at low and mid-latitudes. Weaknesses also occur when analyzing the mean precipitation rates; HOAPS underperforms in the area of the intertropical convergence zone, where OceanRAIN observations show the highest mean precipitation rates. Histograms indicate that this is due to an underestimation of the frequency of moderate to high precipitation rates by HOAPS, which cannot be explained by areal averaging.

scholarly journals Spatial-Temporal Pattern Changes of UTCI in the China-Pakistan Economic Corridor in Recent 40 Years

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 858
Author(s):  
Di Zeng ◽  
Jinkui Wu ◽  
Yaqiong Mu ◽  
Mingshan Deng ◽  
Yanqiang Wei ◽  
...  
Keyword(s):  
Thermal Environment ◽  
Linear Trend ◽  
Temporal Variations ◽  
Reanalysis Data ◽  
Climate Index ◽  
Positive Trend ◽  
Growth Trend ◽  
Weather Forecasts ◽  
European Centre ◽  
Medium Range

This paper investigated the spatial and temporal variations of the Universal Thermal Climate Index (UTCI) of the China-Pakistan Economic Corridor (CPEC) from 1979 to 2018. The European Centre for Medium-Range Weather Forecasts Re-Analysis-Interim (ERA-Interim) reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) is selected for UTCI calculation in the region and analyzed by a linear trend and correlation analysis. The results showed that (1) the UTCI of CPEC is decreased with the increase of latitude and altitude. There is obvious spatial heterogeneity in the seasonal scale and the spatial distribution of different thermal stress categories. (2) UTCI generally exhibited a positive trend of 0.33 °C/10a over the past 40 years, and the seasonal variation characteristics of UTCI show an upward trend in all four seasons, of which spring is the fastest. On the space scale, the growth trend has significant spatial variations. (3) Temperature has a positive correlation with UTCI. The influence of temperature on UTCI is greater than that of wind speed. The results of this study will be helpful for regional planning and also contribute to comprehending the characteristics of the thermal environment in CPEC.

scholarly journals Comparisons of polar processing diagnostics from 34 years of the ERA-Interim and MERRA reanalyses

2015 ◽  
Vol 15 (7) ◽  
pp. 3873-3892 ◽  
Author(s):  
Z. D. Lawrence ◽  
G. L. Manney ◽  
K. Minschwaner ◽  
M. L. Santee ◽  
A. Lambert
Keyword(s):  
Meteorological Data ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Cloud Formation ◽  
Data Sets ◽  
Weather Forecasts ◽  
Stratospheric Temperature ◽  
Vortex Size ◽  
Comprehensive Comparison ◽  
Modern Era

Abstract. We present a comprehensive comparison of polar processing diagnostics derived from the National Aeronautics and Space Administration (NASA) Modern Era Retrospective-analysis for Research and Applications (MERRA) and the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA-Interim). We use diagnostics that focus on meteorological conditions related to stratospheric chemical ozone loss based on temperatures, polar vortex dynamics, and air parcel trajectories to evaluate the effects these reanalyses might have on polar processing studies. Our results show that the agreement between MERRA and ERA-Interim changes significantly over the 34 years from 1979 to 2013 in both hemispheres and in many cases improves. By comparing our diagnostics during five time periods when an increasing number of higher-quality observations were brought into these reanalyses, we show how changes in the data assimilation systems (DAS) of MERRA and ERA-Interim affected their meteorological data. Many of our stratospheric temperature diagnostics show a convergence toward significantly better agreement, in both hemispheres, after 2001 when Aqua and GOES (Geostationary Operational Environmental Satellite) radiances were introduced into the DAS. Other diagnostics, such as the winter mean volume of air with temperatures below polar stratospheric cloud formation thresholds (VPSC) and some diagnostics of polar vortex size and strength, do not show improved agreement between the two reanalyses in recent years when data inputs into the DAS were more comprehensive. The polar processing diagnostics calculated from MERRA and ERA-Interim agree much better than those calculated from earlier reanalysis data sets. We still, however, see fairly large differences in many of the diagnostics in years prior to 2002, raising the possibility that the choice of one reanalysis over another could significantly influence the results of polar processing studies. After 2002, we see overall good agreement among the diagnostics, which demonstrates that the ERA-Interim and MERRA reanalyses are equally appropriate choices for polar processing studies of recent Arctic and Antarctic winters.

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