711 Matching Annotations
  1. Sep 2024
    1. according to which it is only the mass convergence aloft that has an effect on the hydrostatic surface pressure

      Wallace and Hobbs Eq. 7.41 is just not right

    1. Scientific colour maps

      Usebarlow is a hashtag about it, color blindness friendly and linear perceptual gradients color tables

  2. Aug 2024
  3. Feb 2024
    1. apparently nonstationary visualbehavior arises because of the non-Gaussian statistic

      anyway the point is: simple 'red' noise can have surprisingly large or long-lasting excursions, in fact random walks diverge, the drunk will never find that lamp again....

    2. purely random fluctuations expected from stationary timeseries

      stationary but not flat time series

    1. The interactions can result in predator–prey cycles in moisture mode activity and Hadley cell strength that are akin to ITCZ breakdown.

      like the old "index cycles" of the jet stream

    1. iltered water vapor imagery

      another view of hunga tonga explosion

    2. external gravity (or Lamb) waves excited by the Tonga explosion

      What a fascination, Hunga Tonga volcano, other links to cool videos from it:

      global view of time derivative

      back side of planet

  4. Jan 2024
    1. Multi-Radar Multi-Sensor (MRMS) Operational Product Viewer

      Great USA radar data viewer/browser from NSSL

  5. Dec 2023
  6. Nov 2023
    1. Defininations: heatwave: at least three consecutive days in which the maximum 2-meter air temperature exceeds the 90th percentiles.  The consecutive days of heatwave is counted within a month, which is the same in other variables, such as CDD, CSDI, CWD, LCS, and LWS.   cold spell: the minimum 2-meter air temperature be less than the 10th percentiles.   warm spell: the maximum 2-meter air temperature exceeds the 90th percentiles.    percentiles: in this collection they are based on daily temperature and precipitation fields, and calculated using a running window of +/- 7 days centered on each day of the year for the climatology period of 1991-2020 in Version 2 (1981-2010 in Version 1).

      Definitions: a key aspect

    2. Climate Statistics Products

      Extremes Detection detail

    1. maximum number of consecutive days when precipitation < 1 mm

      key crop-relevant dryness indicator

    2. percentage of time when daily max 2-m temperature < 10th percentile

      1990-2020 TIME average guaranteed to be exactly 10% everywhere. Should we check that, for some calendar month?

    3. percentage of time when daily min 2-m temperature

      that is, percentage of DAYS within the month when ...

    1. Monthly Percentiles

      monthly percentiles within 1990-2020 year population of this calendar month, for prectot & DIURNAL mean,max,min T2m

    1. The monthly percentiles indicate atwhich percentile the monthly mean falls relative to the 1991-2020 period.

      monthly or daily same 30-year reference period

    2. ercentiles were calculated using a running window of +/- 7 days centered on each day ofthe year for the climatology period of 1991 through 2020 for version 2 products.

      MERRA2 statistics products, percentiles definition and reference period (1991-2020)

    1. MRMS multi-radar multi-senso

      Great radar viewer and analysis too - used at NWS. Since 2020

    1. Effects of SST on surface wind stress

      maybe Ian wants to see this

    2. Gravity wave packets

      broader smooth waves are evident, as well as the short wavelength packets that draw the eye

  7. Oct 2023
    1. Baiu Front Okinawa

      starts as a front, ends as a cyclone

    2. Column water vapor in the spin-up of an aquaplanet

      Impressive... is it convecting? If not why not?

    3. Rossby wave dispersion

      lovely development of teleconnections

    4. evolving lowpass filtered fields act as a "steering flow” for the high pass filtered perturbations

      just temporal filtering, but it suffices to separate long vs. short waves in spatial scale

    5. Equatorially-trapped waves

      nice to know where to find these

    6. ozone

      the ozone hole, breaks in two at 0:40

    7. PV on the 850 hPa surface

      ERROR! It is PV on the 7mb surface (35km altitude)

    8. strength of the condensation heating in the model can be controlled by specifying the relative humidity

      development takes a little longer with weaker latent heating

    9. both LC1 and LC2

      LC1 and LC2 life cycles (aka "wave breaking" directions) Northern part either swept east (LC1) or left behind (LC2).

    10. a new center develops nearer to the coast and quickly becomes dominant

      new center forms and shreds the vorticity of the old one

    11. intense cyclone comes ashore near San Francisco

      Monterey damage I think I heard?

    12. well defined

      pinhole round center, nice visibility

    13. 10-day interval, six or seven systems

      "six or seven" because "systems" are hard to define! Rivers, Cyclones, ...

    14. shear instability

      Excellent following-the-flow viewpoint!

    15. cold continental air masses flow over the warmer offshore waters

      brief animation, spectacular... brrr, Japan!

    16. Hourly CO concentration

      CO has a lifetime of about a week, for methane (longer lifetime) see next video. Water vapor has a similar lifetime but different sources and sinks.

    17. summer drawdown due to the uptake of CO2 by the boreal forests

      minute 1:00

    18. those shown in Part II move in tandem with features embedded in the base of the updraft, indicative of a deeper structure

      0:27 has nice deep layered wav e clouds above the surface gust front

    19. aerosols are categorized by tint: dust (orange), smoke (red) organic/black carbon (green), and sulfates (white)

      long lovely one, the once a day data assimilation window for tracers sweeps westward it seems.

    1. CONDA_SUBDIR=osx-64 conda create

      prepend conda with this for new Apple M1/M2 chips if ordinary conda -c conda-forge fails

      Successful: CONDA_SUBDIR=osx-64 conda create -n MetPy_arm64 -c conda-forge metpy siphon xarray jupyterlab

  8. Jun 2023
    1. a cloud or moisture feature

      feature based

    2. Satellite Derived Winds

      Derived Motion Vectors, Cloud Track Winds, Cloud Motion Vectors, etc. etc.

    1. Digital Storytelling Tools

      how to blog, hvplot() in Jupyter, Cookbooks from Pythia

    2. Jon Thielen

      two new xarray tricks: 1. drop-in speedup for pandas 2. .hvplot() instead of plot()

  9. May 2023
  10. Mar 2023
    1. The Brave browser is

      Brave browser instructions, to keep login cookie.

      go to cookies<br /> brave://settings/cookies

      Under Allow, add [*.]bjfhmglciegochdpefhhlphglcehbmek

  11. Jan 2023
  12. Nov 2022
    1. Up-scale growth thus occurs as a continuing amplification oflarge scales after small scales saturate, which begs the question of what sets the shape of the saturation(climatological) power spectra. Wind spectra are nearly power-law with a logarithmic slope of about −5/3in the free troposphere, remarkably so in the 2D runs and clearly distinct from slope −2 (a null hypoth-esis of spectrally white wind divergence). A common interpretation of −5/3 slope − as indicative of a cas-cade, a steady conservative transfer of energy from source to sink scales by interactions that are local inlog-wavelength space − is hard to apply to these moist tropical waves.

      predictability aspects of convectively coupled waves. When the cascade example is elevated to paradigm, it cuts off the view to wider pastures -- not that I have a counter-theory, just a sense that a question can be asked starkly

  13. Oct 2022
    1. gmao/geos-cf

      GEOS GMAO Composition forecasts 1440x720 grids! since 2019 or so

  14. Sep 2022
  15. Aug 2022
    1. that more knowledge about climateintervention approaches and their consequences will help society make informed, justdecisions about the deployment of climate intervention. AGU is not taking a position aboutspecific climate interventions, but AGU is making the case that a robust body of scientificevidence about climate intervention and an ethical framework should be available

      The grammatical singular word "society" is quite problematic here, in my view. Likewise, the premise of 'support research first, with ethics relegated to adjectives like responsible in a framework' is a problematic overarching framework. Perhaps to be expected from a scientific society, a research = funding = activity = influence maximizing enterprise, but as likely in my view to be a cause as a preventer of ethically good outcomes overall.

    1. You can try Via by clicking the “Paste a link” button at the top of the page.

      or just notice what it does: it prepends to the URL, for instance cnn.com becomes https://via.hypothes.is/cnn.com

  16. May 2022
    1. CONCEPT MAPPING: A USEFUL TOOL FOR SCIENCE EDUCATION

      graphs of networks, mind maps, powerful stuff compared to bulleted lists of words

  17. Apr 2022
    1. Wereserve some flexibility in how exactly to define these quantities

      true inhibition (lower-tropospheric environmental T sensitivity) is over a layer far deeper than parcel CIN, as Fig. 5a of my much later paper could finally show, thanks to Zhiming Kuang's mathematical powers

    1. define the so-called null hypothesis, which in some sense states the opposite

      null hypothesis insignificance test

  18. Mar 2022
    1. Distribution of Helicity, CAPE, and Shear in Tropical Cyclones

      Tornado parameters in hurricanes - Molinari

    1. Factors contributing to tornadogenesis in landfalling Gulf of Mexico tropical cyclones

      appplications journal, but a review perhaps

    1. The dominant deep convective heating process changes from latent heating at low levels to eddy heat-flux convergence in the upper troposphere. This requires a substantial updraught-environment temperature difference

      This is the fundamental reason that convective buoyancy is plentiful is upper levels. Because the SIGN of buopyancy is crucial, but the value not so important, low-level environmental density (which can make near-zero lifted-parcel buoyancy be slightly positive or negative) is more important than density (T) at upper levels in modulating convection in tropical waves.

  19. Nov 2021
  20. weather.rsmas.miami.edu weather.rsmas.miami.edu
    1. within

      no, to horizontal variations (one column deviating from the average)

  21. Oct 2021
  22. weather.rsmas.miami.edu weather.rsmas.miami.edu
    1. ifference between an airparcel and its surrounding environmen

      See, it is a couple steps from the basic dw/dt equation to "warm air rises"!

    2. The dynamics of many mesoscale phenomena are oftenmore intuitive if the vertical momentum equation is writtenin terms of a buoyancy force and a vertical perturbationpressure gradient force.

      Here is the basic definition of buoyancy

    1. portrait of the emergence structure of the system.

      If “scale” is well defined

    2. hose which minimise dynamical dependence) characterise emergenc

      But of course

    3. epimorphism
    4. in the context of the environment E

      A generalization

    5. microscopic history adds nothing to the capacity of the macroscopic variable to self-predic

      Dynamical independence. A protectorate?

  23. Sep 2021
    1. Widths of the earliest detectable low-level updrafts associated with sustained precipitating deep convection were ~3–5 km, larger than updrafts associated with surrounding boundary layer turbulence (~1–3 km wide)

      Bigger updrafts are better

    1. close agreement with Fig. 1.11.

      The jet stream is in thermal wind balance with a latitudinal T gradient. The coriolis force holds up a wall of cold air, so gravity can’t pull it down

    1. The rotational and divergent components of atmospheric circulation on tidally locked planets

      How I found this paper

    1. We apply theHelmholtz decomposition to the horizontal velocity fields out-put from two well-studied general circulation mode

      Windspharm package

    2. 25

      J. A. Dutton,The Ceaseless Wind. An Introduction to the Theory of AtmosphericMotion(McGraw-Hill, New York, NY, 1976)

      Not exactly "extensive"!

      KE "decomposition" isn't right, there is a cross term

      Energetics (cross term as interaction) seems more promising

      Using vorticity budgets through time to infer the divergent flow, using $$d/dt(\zeta) = \zeta \times \delta$$ are called the "chi problem" (Sardeshmukh 1993).

    3. a superrotating equatorial jet, planetary-scale station-ary waves, and thermally driven overturning circulatio

      The mean flow. How about the weather?

    4. tidally locked planets
    5. The two physical components of the rotational circulation in Fig. 2

      zonal mean plus eddy as usual

    6. Helmholtz decomposition of horizontal velocityufor the terrestrial simulation at 0.4 bar.

      Upper levels on Earthlike planet

    7. zonal-mean jet (red) and the eddy stationary waves (green

      zonal mean jet at equator, why? eddy momentum flux, why?

    8. Divergent, overturning circulation (blue) rises at thesubstellar point

      hot air rises, check

    9. dividing the circulation of a terrestrial tidallylocked atmosphere into rotational and divergent componentscorresponds to a division into two physically meaningful circu-lations. The rotational circulation is primarily composed of thestationary Rossby waves forced by the divergent circulation andthe zonal-mean jet produced by the stationary part of the atmo-spheric circulation.

      Summary

    10. Rotation rateΩ(s−1)7.29×10−6

      Same rotation rate as Earth

    11. height and velocity fields at 0.4 bar

      for Earth like planet with a hot substellar longitude at the equator

    Annotators

    1. The energetics of this system describe exchanges among the divergent and the rotational energy components. The energy equations are as follows.

      Energetics of divergent-rotational interactions

    1. Boyle, James S. October 1996, 34 pp.  The 200 hPa kinetic energy is represented by means of the spherical harmonic components for the AMIP simulations, the NCEP/NCAR reanalysis and the ECMWF reanalysis(ERA). The data used are the monthly mean wind fields for 1979 to 1988. The kinetic energy is decomposed into the divergent (DKE) and rotational (RKE) components and emphasis is placed on examining the former.

      but they are not orthogonal, so this is not a true decomposition of KE

  24. Aug 2021
    1. Like Greg, I read a collection of rationality blogs—Marginal Revolution, Farnam Street, Interfluidity, Crooked Timber.

      Blogs to check out

    2. Why Is It So Hard to Be Rational?

      Maybe useful for class?

  25. Jun 2021
    1. f the major premise is made sensible by making itprobabilistic, not absolute, the syllogism becomes for-mally incorrect and leads to a conclusion that is not sen-sible

      Null hypothesis significance testing is problematic

  26. May 2021
    1. Norbert Wiener, a child prodigy and a great mathematician, coined the term 'cybernetics' to characterize a very general science of 'control and communication in the animal and machine'. It brought together concepts from engineering, the study of the nervous system and statistical mechanics (e.g. entropy). From these he developed concepts that have become pervasive through science (especially biology and computing) and common parlance: 'in-formation', 'message', 'feedback' and 'control'. He wrote, 'the thought of every age is reflected in its technique . . . If the seventeenth and early eighteenth centuries are the age of clocks, and the later eighteenth and nineteenth centuries constitute the age of steam engines, the present time is the age of communication and control.'

      He coined "feedback"?? I can't imagine a scientific language without that term. Profound.

    1. where slow and shigh are respectively the saturated moist entropy averaged over the altitude ranges of 1–3 km and 5–7 km

      II defined 550-430 mb is 5-7km, 890-700 is 1-3km

    2. where is threshold entropy, defined as the average of the saturated moist entropy in the 1.5–2 km layer, minus the boundary layer moist entropy sbl averaged over the 0–1 km layer

      DCIN defined

    1. he MPO Ph.D. degree requires a minimum of 30 course credits, of which a minimum of 9 course credits should be taken from 700 level courses.

      30 COURSE credits, at least 9 from 700 level classes

      total credits are 60

    2. at least one 3-credit course outside the MPOprogram

      a little vague perhaps -- clarify for next year

    3. MPO) GRADUATE HANDBOOK,2020-2021

      MPO program handbook

  27. Apr 2021
  28. Mar 2021
    1. vertical motion

      units don't match Fig. 9c

    2. DYNAMO data and RAs

      MERRA-2 facts

    3. A peculiar feature in MERRA-2 is that its moisture analysis increment (estimated by budget residual) is positive and largest even though CWV anomalies are larger than those in the other RAs

      MERRA-2 facts

    4. ratio of anomalous OLR (a proxy of column longwave heating) to precipitation

      latent heat of radiation

    5. The contribution of LW to MSE propagation in MERRA-2 and JRA-55 is relatively small, which is likely related to the relatively weak cloud–radiation feedback strength

      MERRA-2 facts

    6. the models used to create the modern RAs need additional MSE source to maintain MJO MSE anomalies

      MERRA-2 facts

    7. In MERRA-2 (JRA-55), horizontal MSE advection tends to dampen (amplify) MSE anomalies

      MERRA-2 facts

    8. Over the Indo-Pacific warm pool, the mean MSE is relatively high in MERRA-2 and ERA-I

      MERRA-2 facts

  29. Feb 2021
    1. LRP highlights the regionsof greater relevance for the ANN to predict the year by propagating an output sample back-ward through the frozen nodes of the ANN until it reaches the input layer

      positive-only map? Why is the sign lost?

    1. virtual sv(red broken), moist h

      The virtual effect of vapor (lowering air density by its lighter molecular weight) involves (0.61q)T, about 0.2 K for a 1 g/kg vapor increment. If that same 1g/kg of vapor's latent heat is released (so that it lowers the air's density by warming), it increases T by (\(L/C_p\)) or 2.5C. This factor of about (2.5)/0.2 = 12.5 can be seen graphically here at low levels, comparing \(s_v-s\) to \(h-s\).

      By the way, if that 1 g/kg of condensed water is carried by the parcel (falling at its terminal velocity), its contribution to buoyancy is g/1000, the density equivalent of cooling the air by about 0.3K.

    1. Total precipitation

      Where the rubber meets the muddy roads

    2. “reforecasts” of the weather, that is, retrospective forecasts spanning the period 2000-2019

      2000-2019

    3. Precipitable water (kg m​-2​, i.e., mm)

      Reforecast set

    1. It is not currently possible to “un-flag” an annotation — if an annotation is flagged by mistake, the group creator can choose not to hide it.

      Wow, this is so emblematic of the age... any person can taint another irrevocably with a flag!

      And an accident cannot be undone!

      Now when I screen share on Zoom to discuss our document, everyone will see a big red flag.

  30. Jan 2021
    1. as-yet-undiscovered organizing principles might be at work at the mesoscopic scale, intermediate between atomic and macroscopic dimensions

      plenty to do

    1. a damaged species: associate professors. Long forgotten, these tenured professors find themselves burdened with extensive service and administrative tasks

      Hmm, I thought it was the other way around: more tedious forms of service (because of rules requiring full professor status) awaited after promotion, so I lingered a long time as Associate.

  31. Nov 2020
  32. Oct 2020
    1. background

      The mean of all cases

    2. Advζ, AdvT, and the Q term, respectively,

      These are called QGO_PVA (positie vorticity advection above), QGO_WA (warm advection), and QGO_dia (for diabatic). The sum QGO_PVA + QGO_WA = QGO_adia, for adiabatic, the traditiional view of winter QG omega.

    3. The total ω may be separated into a component explained by the QG ω equation (ωqg) and the remainder [ωaqg, calculated as a residual term in Eq. (2)]. A significant advantage of the QG ω equation is its linearity, and thus, we may directly decompose ωqg into components forced by the large-scale advective forcings and diabatic heating.

      All those derivatives (and their inverse) are a linear operation, op(A + B + C) = op(A) + op(B) + op(C)

    4. The QG ω equation may be written as

      Eq. 1

    1. thermal efficiency of the atmospheric heat engine isless than 1%

      KE is a tiny fraction of macroscopic (thermodynamic) energy

    2. there will alwaysremain some degree of uncertainty (or errors) inthe initial conditions and, due to the nonlinearityof atmospheric motions, these errors inevitablyamplify with time. Beyond some threshold forecastinterval the forecast fields are, on average, no morelike the observed fields against which they are veri-fied than two randomly chosen observed fields forthe same time of year are like one another. For theextratropical atmosphere this so-called limit ofdeterministic predictabilityis believed to be on theorder of 2 weeks

      predictability limit: fundamental, inescapable

    3. cross-isobar flow V is the one and onlysource term

      Local equation for KE

    4. It can be shownthat, in the integral over the entire mass of theatmosphere, the generation of kinetic energy by theV term in (7.42) is equal to the release ofpotential energy associated with the rising of warmair and sinking of cold air.

      perhaps in flux form...\(\overline{\alpha \omega}\) is the term

  33. Sep 2020
    1. 0

      Zero, PLUS a curl-of-friction term (viscous effects), PLUS a vertical derivative of heating term. These are fundamental drivers and dampers that make otherwise-conservation have interesting situations rather than 0=0 forever.

    2. Exercises

      Exercises section

    3. 1 PVU106m2s1K kg1

      At least they didn't put Pascals in there, raw MKS units

    4. Ertel’s19potential vorticity

      EPV, often displayed on an isentropic surface

    1. LLCS consumes far too much boundary layer moisture

      LLCS includes dry PBL convection, while GR excludes it I think.

    2. standard value used in our simulations is the “pure mixing time scale” of 3,600 s

      LLCS is relaxation toward an adjusted (neutralized) target.

      The target is defined by an upward process of 100% mixing of adjacent layers between lowest unstable parcel and the top level where the crest of this upward-mixing pile of air, lifted one more level, is no longer warmer than ambient.

    3. the bottom row shows the second eigenvectors, V2

      I wonder if the value 700 in the sampler (700-100mb heating rate) is creeping in here?

    4. Hence, instead of truncating, we rotate β and γ back into θ,q on levels by forming the 2m component vector and the 2m × 2m matrix to interpret our results

      Inputs are rotated back into profile for plotting

    5. the vast majority of output convective behavior can be described with relatively few eigenvectors. We typically retain two or three for discussion in the results sections and use 10 when the emulators are run online as part of the GCM

      output truncation is here

    6. We predict Q from P rather than predicting Y from X because correlations between values of θ and q on different vertical levels that could cause large errors in our statistical analysis are avoided

      Orthogonal basis, but not truncated. Maybe the small late-in-the-list modes are no problem to bring along for completeness, since their spurious (sample-specific) correlations are down-weighted by their smallness. Truncation occurs below, actually.

    7. Cases from the equally spaced group deemed nonconvecting (cpΔθtrop < 0.05 MJ m−2) are then discarded, as are an equal number of nonconvecting cases. This leaves an equal number of convecting and nonconvecting cases

      10K/d is the threshold

    8. The choice of 60,000 cases was made, as it is realistic to perform analysis on matrices of this size with available computing resources. It is found that using smaller sample sizes has little effect on accuracy

      matrix software is great

    9. nonconvecting cases (defined as cpΔθtrop <0.05 MJ m−2, equivalent to a temperature change ΔTtrop  ≃ 10.1 K day−1,

      10K/d heating of 700-100mb layer is not "no convection"!!

    10. the cases closest to 30,000 equally spaced values of cpΔθtrop from its minimum to its maximum value

      No averaging, just sampling to an equally spaced grid in the space of range

    11. A two‐step linear statistical emulator is used

      Linear closure, but with a trigger. But trigger is really just a screening of their training dataset for places where the emulated schemes themselves have convection disabled (trigger off).

    12. we form a “case.”

      state variables are X, tendencies are Y

    13. The overall aim is not to replace conventional parameterization nor to improve GCM integration speed but to understand our parameterizations in the context of process knowledge and provide tools for parameterization development and interpretation of climate model projections.

      Right, just making sense of the situation -- speed is no good if direction is unclear.

    14. The derived response matrices must also be put in the GCM in place of the original parameterization, as was done by Kelly et al. (2017) and Mapes et al. (2019)

      Yay, our dream

    1. thickness of the layer

      delta-Z is a thickness

    2. Z

      This would be clearer as a delta-Z: it is a height difference or thickness of a mass (p) layer

    3. Cis referred to as the circulation
    4. Exercises

      Exercises

    1. spatial organization of tropical deep convection, can manifest itselfin two ways: through a decrease in the total area covered by convection and/or through a decrease in thenumber of convective areas

      two kinds of organization

    1. (a) geography-relative and (b) recurvature-relative frameworks.

      A slight sleight of hand, shifting longitudes

    2. Recurvature-relative composite analyses of all recurving WNP TCs

      Archambault et al. composite v250'

    3. zonal group speeds based on the leading edge [cg = 42° day−1 (36.5 m s−1)] and peak amplitude [cg = 37° day−1 (32.1 m s−1)] of the RWT, respectively, whereas the yellow arrow indicates the estimated Rossby wave zonal phase speed [cp = 6° day−1 (5.2 m s−1)]

      group vs. phase velocities

    1. David (1997)−2.0543Soulik (2006)−1.7317Susan (1988)−2.0144Mamie (1985)−1.6818Dale (1996)−2.0045Phanfone (2002)−1.6719Thelma (1980)−2.0046Agnes (1981)−1.6720Lola (1986)−1.9747Dianmu (2004)−1.67

      Team 4 do these

    2. Polly (1995)−1.9248Ann (1999)−1.6622Dan (1995)−1.8949Podul (2001)−1.6623Nabi (2005)−1.8850Ma-on (2004)−1.6524Dinah (1987)−1.8751Krosa (2001)−1.6325Faxai (2007)−1.8752Winnie (1997)−1.63

      Team 5 do these

    3. Xangsane (2000)−2.0838Forrest (1986)−1.7512Stella (1998)−2.0839Kinna (1991)−1.7513Choi-wan (2009)−2.0840Irma (1981)−1.7414Vanessa (1984)−2.0641Marge (1983)−1.7315Elsie (1992)−2.0642Gay (1981)−1.73

      Team 3 do these

    4. Orchid (1980)−2.3133Cecil (1993)−1.767Nanmadol (2004)−2.1834Judy (1982)−1.768Rammasun (2008)−2.1735Irving (1979)−1.769Mireille (1991)−2.1536Owen (1979)−1.7510Songda (2004)−2.1337Flo (1990)−1.75

      Team 2 do these

    5. 1Melor (2009)−2.5828Chaba (2004)−1.832Oscar (1995)−2.5729Colleen (1989)−1.823Hunt (1992)−2.3630Mac (1982)−1.794Haishen (2002)−2.3531Gordon (1982)−1.785Elsie (1981)−2.3232Megi (2004)−1.77

      Team 1 do these

    6. Schematic representation of upper-tropospheric ridge amplification and jet streak intensification associated with divergent TC outflow impinging upon an upper-tropospheric jet stream

      Archambault schematic of ET extratropical transition mechanism of Rossby wave forcing

    7. 54 recurving WNP TCs associated with strong TC–jet stream interactions

      Strong interaction cases table

    8. Recurvature-relative composite Hovmöller diagram

      Hovmuller of v' at 250

    1. meridional wind anomaly (m s−1),

      the money figure, v'250

    2. the asymmetry parameter from the Hart (2003) cyclone phase space2 is calculated from reanalysis data. This parameter provides a measure of the thermal asymmetry across the cyclone and has been used to objectively identify the onset of transition. As in Hart (2003), the onset of transition is defined as when the asymmetry parameter exceeds 10 m and is hereafter referred to as t = 0

      defining "transition" t=0

    3. Anomalies are defined as deviations from a moving-average climatology, meaning that every day of the year has a unique climatology, defined as the average of all daily fields within 14 days of the day of interest during the 32-yr period. This method of computing the climatology has the advantage of producing a smooth climatology from one day to the next.

      anomalies

    1. a sceptical attitude to the widespread view that we can learn about causal processes by constructingDAG models of observational data

      it's the observational part where the subtleties lie

  34. Aug 2020
    1. For a hypothetical conservative tracer,theLagrangian rate of change is identically equal tozero, and the Eulerian rate of change is

      Smoke (which seems to just accumulate) is perhaps like this...

    1. will look the same in any coordinate system

      Coordinate invariance defines vectors. A vector has magnitude and direction, but not location.

    2. there is a simple geometrical way to calculate a⋅b\FLPa\cdot\FLPb, without having to calculate the components of a\FLPa and b\FLPb: a⋅b\FLPa\cdot\FLPb is the product of the length of a\FLPa and the length of b\FLPb times the cosine of the angle between them

      cosine of angle, well defines in any dimensional space

    3. Let us now define a new thing, which we call a⋅a\FLPa\cdot\FLPa. This is not a vector, but a scalar; it is a number that is the same in all coordinate systems, and it is defined to be the sum of the squares of the three components of the vector

      inner product, scalar product

    1. conditional probability: P ( X | Y ) {\displaystyle P(X|Y)} , reads "the probability of X given Y"

      conditional probability - rules the world

    1. A set is a gathering together into a whole of definite, distinct objects of our perception [Anschauung] or of our thought—which are called elements of the set.

      So fundamental!

    1. Let us ask, “What is the meaning of the physical laws of Newton, which we write as F=maF=ma? What is the meaning of force, mass, and acceleration?” Well, we can intuitively sense the meaning of mass, and we can define acceleration if we know the meaning of position and time. We shall not discuss those meanings, but shall concentrate on the new concept of force. The answer is equally simple: “If a body is accelerating, then there is a force on it.” That is what Newton’s laws say, so the most precise and beautiful definition of force imaginable might simply be to say that force is the mass of an object times the acceleration. Suppose we have a law which says that the conservation of momentum is valid if the sum of all the external forces is zero; then the question arises, “What does it mean, that the sum of all the external forces is zero?” A pleasant way to define that statement would be: “When the total momentum is a constant, then the sum of the external forces is zero.” There must be something wrong with that, because it is just not saying anything new. If we have discovered a fundamental law, which asserts that the force is equal to the mass times the acceleration, and then define the force to be the mass times the acceleration, we have found out nothing.

      Force as a new concept - or is it just a label?

    1. The word "frequentist" is especially tricky. To philosophers it refers to a particular theory of physical probability, one that has more or less been abandoned. To scientists, on the other hand, "frequentist probability" is just another name for physical (or objective) probability. Those who promote Bayesian inference view "frequentist statistics" as an approach to statistical inference that recognises only physical probabilities.

      name calling between the different camps