data_clean_1是xarray.dataset,我想给转化成dataframe，但是一直报错，这应该怎么解决啊？谢谢
for i in data_h_index:
if select_time[i].split('-')[0] == '2019':
data_clean_1 = data_ow_1.sel(time=select_time[i], longitude=select_lon[i], latitude=select_lat[i],method='nearest')
DT_1 = data_clean_1.to_pandas()
new_data_clean_1 = new_data_clean_1.append([DT_1])
Traceback (most recent call last):
File "D:\e下载\test combine.py", line 104, in <module>
DT_1 = data_clean_1.to_pandas()
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\dataset.py", line 6139, in to_pandas
return pd.Series({k: v.item() for k, v in self.items()})
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\dataset.py", line 6139, in <dictcomp>
return pd.Series({k: v.item() for k, v in self.items()})
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\ops.py", line 203, in func
return _call_possibly_missing_method(self.data, name, args, kwargs)
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\dataarray.py", line 713, in data
return self.variable.data
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\variable.py", line 435, in data
return self.values
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\variable.py", line 608, in values
return _as_array_or_item(self._data)
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\variable.py", line 314, in _as_array_or_item
data = np.asarray(data)
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\indexing.py", line 653, in __array__
self._ensure_cached()
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\indexing.py", line 650, in _ensure_cached
self.array = NumpyIndexingAdapter(np.asarray(self.array))
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\indexing.py", line 623, in __array__
return np.asarray(self.array, dtype=dtype)
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\indexing.py", line 524, in __array__
return np.asarray(array[self.key], dtype=None)
File "D:\anaconda\envs\program1\lib\site-packages\cfgrib\xarray_plugin.py", line 156, in __getitem__
return xr.core.indexing.explicit_indexing_adapter(
File "D:\anaconda\envs\program1\lib\site-packages\xarray\core\indexing.py", line 815, in explicit_indexing_adapter
result = raw_indexing_method(raw_key.tuple)
File "D:\anaconda\envs\program1\lib\site-packages\cfgrib\xarray_plugin.py", line 165, in _getitem
return self.array[key]
File "D:\anaconda\envs\program1\lib\site-packages\cfgrib\dataset.py", line 354, in __getitem__
message = self.index.get_field(message_ids[0]) # type: ignore
File "D:\anaconda\envs\program1\lib\site-packages\cfgrib\messages.py", line 484, in get_field
return ComputedKeysAdapter(self.fieldset[message_id], self.computed_keys)
File "D:\anaconda\envs\program1\lib\site-packages\cfgrib\messages.py", line 344, in __getitem__
return self.message_from_file(file, offset=item)
File "D:\anaconda\envs\program1\lib\site-packages\cfgrib\messages.py", line 340, in message_from_file
return Message.from_file(file, offset, **kwargs)
File "D:\anaconda\envs\program1\lib\site-packages\cfgrib\messages.py", line 93, in from_file
file.seek(offset)
OSError: [Errno 22] Invalid argument
该段代码缺少对 new_data_clean_1 的初始化，因此在第一次执行 append 操作时会报错。您需要在使用 append 操作之前对 new_data_clean_1 进行初始化。
您可以将以下代码添加到您的程序中，以在使用 append 操作之前初始化 new_data_clean_1：
import pandas as pd
new_data_clean_1 = pd.DataFrame()
```python
此外，还需要确保在程序的其他部分中已经定义了 data_h_index、select_time、select_lon、select_lat 和 data_ow_1，否则也会报错。