Earth Engine中GFS每日热浪计数器动画迭代累加函数失效问题

我正在制作一个热浪发展动画，核心流程如下：

1. 基于GFS数据计算日均温
2. 将每日数据转换为符合温度阈值（95°F）的掩码
3. 通过迭代累加函数，让影像集合中的每幅图展示截至当日某一像素达到该温度阈值的天数（例如：某像素第1天值为1，第2天变为2；相邻未达标的像素从0变为1，以此呈现热浪的发展与持续）

目前脚本可正常计算并生成每日计数器，但迭代累加部分无法正常工作。将代码中的print(ui.Thumbnail(cumulative,gifParams))替换为print(ui.Thumbnail(counter,gifParams))后可正常运行，说明问题出在累加脚本部分，怀疑存在逻辑或类型转换错误。

原累加函数的逻辑错误：每次迭代时将整个历史影像列表转为ImageCollection求和，这会重复累加所有历史数据，而非基于前一天的累加结果加上当日的计数器值。正确的逻辑应该是取列表中的最后一幅累加影像，与当日计数器影像相加，再将新的累加结果加入列表。

/*
Data goals: convert GFS to daily, create consecutive and iterative day counters for 
pixels that meet set temperature thresholds

ex. a GIF that shows by day how many days up to then have reached tk temperature.
*/

//set bounds for data extracts, GIFS
var bounds = geometry 

//start and end dates
var startDate = ee.Date('2023-07-01')

var endDate = ee.Date('2023-07-31')

//pull GFS data, filter to forecast_hour = 0 (actual data, and one value per hour) and temp
var dataset = ee.ImageCollection('NOAA/GFS0P25') 
                  .filter(ee.Filter.date(startDate, endDate))
                  .filter(ee.Filter.eq('forecast_hours',0))
                  .select('temperature_2m_above_ground')
                  
// Calc number of days between start and end dates.
var nDays = ee.Number(endDate.difference(startDate, 'day'));

// Enumerate a list of days.
var daysList = ee.List.sequence(0, nDays.subtract(1));

// Map over the list of days to make daily mean composites.
var NEXDayListCol = ee.ImageCollection(daysList.map(function(dayN){
  var t1 = startDate.advance(ee.Number(dayN), 'day');
  var t2 = t1.advance(1, 'day');
  var date = t1
  var dailySum = dataset.filterDate(t1, t2).mean();
  return dailySum.select('temperature_2m_above_ground').multiply(1.8).add(32)
  .set('date', date.format())
}));     

//mask out below 95 F (32.2C)
var masked  = NEXDayListCol.map(function(image){
  return image.mask(image.gte(95));
});

//create counter raster: 1 where temp >=95, 0 otherwise (with mask)
var counter = masked.map(function(image){
  return image.where(image.gte(0),1).rename('count').toFloat().copyProperties({
        source: image,
        properties: ['system:index','date']
      });
})
 
print(masked,'masked counter')

// Initialize with a 0 image matching the first date
var first = ee.List([
  ee.Image(0).set('date', counter.first().get('date')).select([0], ['count'])
]);

// Fixed accumulation function: use previous day's cumulative count + current day's counter
var accumulate = function(image, list) {
  // Get the last cumulative image from the list
  var lastCumulative = ee.Image(ee.List(list).get(-1));
  // Add current day's counter to the last cumulative result
  var newCumulative = lastCumulative.add(image)
    .set('date', image.get('date'));
  // Append the new cumulative image to the list
  return ee.List(list).add(newCumulative);
};

// Create cumulative image collection via iteration
var cumulative = ee.ImageCollection(
  ee.List(counter.iterate(accumulate, first))
);

print(cumulative,'cumulative')

// Define GIF arguments
var gifParams = {
  collection: cumulative,
  dimensions: 100,
  framesPerSecond: 4,
  region: bounds,
  crs: 'EPSG:5070',
  palette: ['e6eff9','f5eeda','fdc47c','f9a224','ee3a43','black'],
  min: 0,
  max: 10,
}

// Define arguments for the getFilmstripThumbURL function parameters.
var filmArgs = {
  dimensions: 100,
  framesPerSecond: 4,
  region: bounds,
  crs: 'EPSG:3857',
  min: 0,
  max: 30,
  palette: ['blue', 'purple', 'cyan', 'green', 'yellow', 'red'],
};

var dayVis = {
  min: 1,
  max: 30,
  palette: ['black','red'],
};

Map.addLayer(counter.sum(), {}, 'daily sum total test');
print(ui.Thumbnail(cumulative,gifParams))

• 修改accumulate函数逻辑：不再对所有历史影像求和，而是取列表最后一个元素（前一天的累加结果）与当日计数器影像相加，生成新的累加结果
• 确保初始化的first列表与counter集合的日期属性一致，避免后续属性不匹配问题

内容的提问来源于stack exchange，提问作者Carl Churchill